The Most Comprehensive Question Bank for ICSE Class 10 Students
Multiple Choice Questions (MCQs)
1) What is the mechanical advantage of a lever?
a) The ratio of load to effort
b) The distance between the fulcrum and the load
c) The weight of the lever
d) The distance between the fulcrum and the effort
Answer: a) The ratio of load to effort
Explanation: The mechanical advantage of a lever is the ratio of the force exerted by the lever (load) to the force applied on the lever (effort).
2) Which class of lever has the effort located between the fulcrum and the load?
a) Class I
b) Class II
c) Class III
d) None of the above
Answer: c) Class III
Explanation: In Class III levers, the effort is applied between the fulcrum and the load, resulting in a mechanical advantage less than 1.
3) In a single movable pulley, what is the relationship between the effort and the load?
a) The effort is half of the load
b) The effort is twice the load
c) The effort is equal to the load
d) The effort is four times the load
Answer: a) The effort is half of the load
Explanation: In a single movable pulley, the effort required is half of the load due to the mechanical advantage of 2.
4) For a machine with a velocity ratio of 4 and an efficiency of 50%, what is the mechanical advantage?
a) 8
b) 4
c) 2
d) 1
Answer: c) 2
Explanation: The mechanical advantage (MA) is the product of efficiency (η) and velocity ratio (VR). So, MA = η × VR = 0.5 × 4 = 2.
5) What is the purpose of a block and tackle system?
a) To change the direction of the applied force
b) To decrease the mechanical advantage
c) To increase the mechanical advantage
d) To balance two equal weights
Answer: c) To increase the mechanical advantage
Explanation: A block and tackle system is used to increase the mechanical advantage, allowing a smaller effort to lift a larger load.
6) Which of the following is true for an ideal machine?
a) Mechanical advantage is less than velocity ratio
b) Efficiency is less than 100%
c) Work output is equal to work input
d) It requires more effort to do the same work
Answer: c) Work output is equal to work input
Explanation: In an ideal machine, there are no energy losses due to friction, so the work output is equal to the work input, and its efficiency is 100%.
7) How is the efficiency of a machine calculated?
a) Ratio of work output to work input
b) Product of mechanical advantage and velocity ratio
c) Sum of mechanical advantage and velocity ratio
d) Difference between mechanical advantage and velocity ratio
Answer: a) Ratio of work output to work input
Explanation: The efficiency of a machine is calculated as the ratio of the work done by the machine (work output) to the work done on the machine (work input).
8) What is the velocity ratio (VR) of a machine?
a) The ratio of the velocity of effort to the velocity of load
b) The ratio of mechanical advantage to efficiency
c) The distance covered by effort to the distance covered by load
d) The weight of the machine divided by the effort applied
Answer: a) The ratio of the velocity of effort to the velocity of load
Explanation: The velocity ratio of a machine is defined as the ratio of the velocity of effort to the velocity of the load.
9) In which class of levers is the fulcrum located between the effort and the load?
a) Class I
b) Class II
c) Class III
d) Class IV
Answer: a) Class I
Explanation: In Class I levers, the fulcrum is located between the effort and the load. Examples include seesaws and crowbars.
10) What factor primarily affects the efficiency of a practical machine?
a) The weight of the machine
b) The color of the machine
c) Friction and other energy losses
d) The size of the machine
Answer: c) Friction and other energy losses
Explanation: The efficiency of a practical machine is primarily affected by friction and other forms of energy losses, which reduce the output work compared to the input work.
11) A lever has an effort arm of 4 meters and a load arm of 2 meters. What is its mechanical advantage?
a) 0.5
b) 1
c) 2
d) 8
Answer: c) 2
Explanation: The mechanical advantage (MA) of a lever is the ratio of the effort arm to the load arm. MA = Effort arm / Load arm = 4m / 2m = 2.
12) Which machine is typically used to change the direction of the applied force without altering the force magnitude?
a) A movable pulley
b) A fixed pulley
c) A lever
d) An inclined plane
Answer: b) A fixed pulley
Explanation: A fixed pulley is primarily used to change the direction of the applied force without changing the magnitude of the force.
13) In a practical machine, why is the mechanical advantage (MA) usually less than the velocity ratio (VR)?
a) Because of the increased speed of the machine
b) Due to energy losses, primarily from friction
c) Because the load is always heavier than the effort
d) Due to the machine’s design
Answer: b) Due to energy losses, primarily from friction
Explanation: In practical machines, MA is usually less than VR due to energy losses, primarily from friction, which reduces the output force compared to the ideal scenario.
14) What is the primary use of a pulley system in machines?
a) To increase force
b) To decrease force
c) To measure force
d) To stabilize force
Answer: a) To increase force
Explanation: The primary use of a pulley system in machines is to increase force, allowing a smaller effort to move a larger load.
15) Which type of machine is an example of a speed multiplier?
a) Class I lever with a long load arm
b) Class II lever with a long effort arm
c) Class III lever with a short effort arm
d) Fixed pulley with equal arm lengths
Answer: c) Class III lever with a short effort arm
Explanation: Class III levers with a short effort arm act as speed multipliers because they allow a larger displacement of the load for a smaller displacement of the effort.
16) A lever has an effort arm of 2 meters and a load arm of 1 meter. What type of lever is it, and what is its mechanical advantage?
a) Class I lever; MA = 0.5
b) Class II lever; MA = 2
c) Class I lever; MA = 2
d) Class III lever; MA = 1
Answer: b) Class II lever; MA = 2
Explanation: This is a Class II lever where the load is between the effort and the fulcrum, and the mechanical advantage (MA) is the ratio of the effort arm to the load arm, which is 2 meters / 1 meter = 2.
17) Which statement is true regarding an ideal machine?
a) Its efficiency is always less than 100%.
b) Its mechanical advantage is equal to its velocity ratio.
c) It requires more effort than practical machines.
d) It always multiplies speed, not force.
Answer: b) Its mechanical advantage is equal to its velocity ratio.
Explanation: In an ideal machine, due to the absence of friction and other losses, the mechanical advantage is equal to the velocity ratio.
18) Why is a single movable pulley considered a force multiplier?
a) Because it increases the speed of the effort
b) Because it decreases the direction of the effort
c) Because it allows a smaller effort to lift a larger load
d) Because it reduces the weight of the load
Answer: c) Because it allows a smaller effort to lift a larger load
Explanation: A single movable pulley is considered a force multiplier because it enables lifting a larger load with a smaller effort, effectively doubling the force applied.
19) In a block and tackle system with 3 pulleys, what is the ideal mechanical advantage?
a) 1.5
b) 3
c) 6
d) 9
Answer: b) 3
Explanation: In a block and tackle system, the ideal mechanical advantage is equal to the number of strands supporting the load. With 3 pulleys, the mechanical advantage is 3.
20) What is the main reason for the efficiency of a practical machine being less than 100%?
a) The design of the machine
b) The color and material of the machine
c) Energy losses due to friction and other factors
d) The complexity of the machine
Answer: c) Energy losses due to friction and other factors
Explanation: The efficiency of a practical machine is less than 100% primarily due to energy losses, such as friction between moving parts and air resistance.
21) What is the function of a lever in a machine?
a) To change the direction of the applied force
b) To increase or decrease the force applied
c) To measure the force applied
d) To stabilize the machine
Answer: b) To increase or decrease the force applied
Explanation: A lever in a machine is used to increase or decrease the force applied. It can either act as a force multiplier or a speed multiplier depending on its class and the relative lengths of the effort and load arms.
22) For a lever with an effort arm twice as long as the load arm, which of the following is true?
a) It acts as a speed multiplier.
b) It has a mechanical advantage of 0.5.
c) It is always a Class I lever.
d) It acts as a force multiplier.
Answer: d) It acts as a force multiplier.
Explanation: When the effort arm is longer than the load arm, the lever acts as a force multiplier. The mechanical advantage is greater than 1 (in this case, 2), allowing a smaller effort to move a larger load.
23) What is the purpose of using a block and tackle system in lifting heavy objects?
a) To decrease the distance over which the effort is applied
b) To increase the force applied to the object
c) To reduce the effort needed to lift the object
d) To change the direction of the applied force
Answer: c) To reduce the effort needed to lift the object
Explanation: The primary purpose of using a block and tackle system in lifting heavy objects is to reduce the effort needed. By increasing the mechanical advantage, a smaller effort can lift a heavier load.
24) What happens to the mechanical advantage of a lever if the length of the effort arm is decreased while keeping the load arm constant?
a) It increases
b) It decreases
c) It remains the same
d) It becomes zero
Answer: b) It decreases
Explanation: The mechanical advantage of a lever is the ratio of the effort arm to the load arm. Decreasing the length of the effort arm while keeping the load arm constant will reduce this ratio, thus decreasing the mechanical advantage.
25) In the context of simple machines, what does efficiency describe?
a) The ratio of velocity ratio to mechanical advantage
b) The ratio of mechanical advantage to velocity ratio
c) The percentage of work input that is converted to useful work output
d) The amount of force that the machine can apply
Answer: c) The percentage of work input that is converted to useful work output
Explanation: Efficiency in simple machines describes the percentage of work input that is successfully converted into useful work output, taking into account losses like friction.
26) A system of pulleys is designed such that the effort moves three times the distance that the load moves. What is the velocity ratio of this system?
a) 1
b) 3
c) 1/3
d) 9
Answer: b) 3
Explanation: The velocity ratio of a pulley system is the ratio of the distance moved by the effort to the distance moved by the load. If the effort moves three times the distance of the load, the velocity ratio is 3.
27) In a class I lever, if the effort arm is half the length of the load arm, what is the mechanical advantage?
a) 0.5
b) 1
c) 2
d) 4
Answer: a) 0.5
Explanation: The mechanical advantage of a lever is the ratio of the effort arm to the load arm. If the effort arm is half the length of the load arm, the mechanical advantage is 0.5, indicating that the effort required is double the load.
28) What is the primary function of a fixed pulley?
a) To increase the mechanical advantage
b) To decrease the effort required
c) To change the direction of the applied effort
d) To multiply the speed of the effort
Answer: c) To change the direction of the applied effort
Explanation: The primary function of a fixed pulley is to change the direction of the applied effort. It does not increase the mechanical advantage or decrease the effort required.
29) A machine with a velocity ratio of 5 and an efficiency of 80% will have a mechanical advantage of:
a) 4
b) 5
c) 6.25
d) 8
Answer: a) 4
Explanation: The mechanical advantage (MA) is calculated by multiplying the velocity ratio (VR) by the efficiency (η). Here, MA = VR × η = 5 × 0.8 = 4.
30) Which type of pulley system will have a mechanical advantage greater than 1?
a) Single fixed pulley
b) Single movable pulley
c) Both a and b
d) Neither a nor b
Answer: b) Single movable pulley
Explanation: A single movable pulley has a mechanical advantage greater than 1, typically 2, allowing a smaller effort to lift a larger load. A single fixed pulley has a mechanical advantage of 1.
31) How is the effort arm related to the load arm in a Class II lever to achieve mechanical advantage greater than 1?
a) The effort arm is shorter than the load arm
b) The effort arm is longer than the load arm
c) The effort arm and load arm are of equal length
d) The length of the effort arm is irrelevant
Answer: b) The effort arm is longer than the load arm
Explanation: In a Class II lever, for achieving a mechanical advantage greater than 1, the effort arm must be longer than the load arm. This arrangement allows a smaller effort to lift a larger load.
32) What is the main advantage of using a block and tackle system with multiple pulleys over a single pulley system?
a) It requires less space
b) It increases the mechanical advantage
c) It reduces the weight of the load
d) It increases the speed of lifting the load
Answer: b) It increases the mechanical advantage
Explanation: A block and tackle system with multiple pulleys is used primarily to increase the mechanical advantage, enabling the lifting of heavier loads with less effort compared to a single pulley system.
33) In a Class I lever, if the load arm is three times longer than the effort arm, what is the mechanical advantage?
a) 0.33
b) 1
c) 3
d) 9
Answer: a) 0.33
Explanation: The mechanical advantage of a lever is calculated as the ratio of the effort arm to the load arm. If the load arm is three times longer than the effort arm, the mechanical advantage is 1/3 or 0.33.
34) Which class of lever is typically used in a pair of scissors?
a) Class I
b) Class II
c) Class III
d) Class IV
Answer: a) Class I
Explanation: A pair of scissors is an example of a Class I lever, where the fulcrum is located between the load and the effort.
35) What determines the velocity ratio in a pulley system?
a) The weight of the pulleys
b) The number of pulleys used
c) The strength of the rope
d) The distance between pulleys
Answer: b) The number of pulleys used
Explanation: The velocity ratio in a pulley system is determined by the number of pulleys used. Generally, the velocity ratio is equal to the number of segments of the rope supporting the load.
36) How does friction affect the efficiency of a simple machine?
a) It increases efficiency
b) It decreases efficiency
c) It has no effect on efficiency
d) It only affects the machine’s speed, not efficiency
Answer: b) It decreases efficiency
Explanation: Friction is a significant factor that reduces the efficiency of a simple machine. It causes energy losses, meaning that not all the input work is converted into useful output work.
37) Which statement best describes a Class III lever?
a) The load is between the effort and the fulcrum.
b) The effort is between the load and the fulcrum.
c) The fulcrum is between the load and the effort.
d) The effort and load are on the same side of the fulcrum.
Answer: b) The effort is between the load and the fulcrum.
Explanation: In a Class III lever, the effort is applied between the load and the fulcrum. This setup typically results in a mechanical advantage less than 1.
38) What is the primary reason a single fixed pulley is used?
a) To double the force applied
b) To change the direction of the force applied
c) To increase the distance over which the force is applied
d) To reduce the distance over which the force is applied
Answer: b) To change the direction of the force applied
Explanation: The primary reason to use a single fixed pulley is to change the direction of the force applied. It allows the user to apply force in a more convenient direction, although it does not increase the force.
39) In a lever system, what effect does moving the fulcrum closer to the load have?
a) Increases the mechanical advantage
b) Decreases the mechanical advantage
c) No change in the mechanical advantage
d) The lever becomes inoperable
Answer: b) Decreases the mechanical advantage
Explanation: Moving the fulcrum closer to the load in a lever system decreases the length of the load arm relative to the effort arm, thereby reducing the mechanical advantage.
40) Which factor does not directly influence the mechanical advantage of a lever?
a) Length of the effort arm
b) Length of the load arm
c) Material of the lever
d) Position of the fulcrum
Answer: c) Material of the lever
Explanation: The mechanical advantage of a lever is influenced by the lengths of the effort and load arms and the position of the fulcrum. The material of the lever does not directly affect its mechanical advantage.
41) In a pulley system, what is the effect of adding more pulleys on the effort required to lift a load?
a) Increases the effort
b) Decreases the effort
c) No change in the effort
d) Doubles the effort
Answer: b) Decreases the effort
Explanation: Adding more pulleys to a pulley system increases the mechanical advantage, which in turn decreases the effort required to lift a load.
42) What is the principle behind the operation of a lever?
a) Conservation of energy
b) Principle of moments
c) Newton’s third law of motion
d) Law of conservation of mass
Answer: b) Principle of moments
Explanation: A lever operates on the principle of moments, where the moment (force times distance) on one side of the fulcrum is balanced by the moment on the other side.
43) If the efficiency of a machine is 75%, and its velocity ratio is 4, what is its mechanical advantage?
a) 3
b) 4
c) 5
d) 6
Answer: a) 3
Explanation: The mechanical advantage (MA) is calculated by multiplying the velocity ratio (VR) by the efficiency (η). Here, MA = VR × η = 4 × 0.75 = 3.
44) In which type of lever is the output force (load) greater than the input force (effort)?
a) Class I lever with a long effort arm
b) Class II lever with a long load arm
c) Class III lever with a long effort arm
d) Class III lever with a long load arm
Answer: a) Class I lever with a long effort arm
Explanation: In a Class I lever, if the effort arm is longer than the load arm, the output force (load) can be greater than the input force (effort), acting as a force multiplier.
45) How does the efficiency of a practical machine compare to that of an ideal machine?
a) Higher than the ideal machine
b) Equal to the ideal machine
c) Lower than the ideal machine
d) Unrelated to the ideal machine
Answer: c) Lower than the ideal machine
Explanation: The efficiency of a practical machine is always lower than that of an ideal machine, mainly due to losses such as friction, which are absent in an ideal machine.
46) In a pulley system, what is the primary purpose of using a movable pulley in addition to a fixed pulley?
a) To increase the force applied
b) To change the direction of the applied force
c) To increase the mechanical advantage
d) To stabilize the system
Answer: c) To increase the mechanical advantage
Explanation: The primary purpose of using a movable pulley in addition to a fixed pulley is to increase the mechanical advantage, allowing a smaller effort to lift a larger load.
47) Which statement correctly describes a Class II lever?
a) The fulcrum is at one end, with the effort applied in the middle.
b) The fulcrum is in the middle, with the effort applied at one end.
c) The load is in the middle, with the effort applied at one end.
d) The effort and load are both applied at the same end.
Answer: c) The load is in the middle, with the effort applied at one end.
Explanation: In a Class II lever, the load is positioned between the fulcrum and the effort, often resulting in a mechanical advantage greater than 1.
48) A lever has a load arm of 1.5 meters and an effort arm of 3 meters. What is its mechanical advantage?
a) 0.5
b) 2
c) 3
d) 6
Answer: b) 2
Explanation: The mechanical advantage of a lever is the ratio of the effort arm to the load arm. In this case, it is 3 meters / 1.5 meters = 2.
49) What happens to the efficiency of a simple machine when friction is reduced?
a) It increases
b) It decreases
c) It remains unchanged
d) It becomes unpredictable
Answer: a) It increases
Explanation: Efficiency of a simple machine increases when friction is reduced, as less energy is lost as heat, and more input work is converted into useful output work.
50) Which of the following is an example of a Class III lever?
a) Seesaw
b) Wheelbarrow
c) Tweezers
d) Crowbar
Answer: c) Tweezers
Explanation: Tweezers are an example of a Class III lever, where the effort is applied between the fulcrum and the load.
51) In a block and tackle system, how does the number of pulleys relate to the mechanical advantage?
a) It is directly proportional.
b) It is inversely proportional.
c) It is squared.
d) There is no relation.
Answer: a) It is directly proportional.
Explanation: In a block and tackle system, the mechanical advantage is directly proportional to the number of pulleys used. More pulleys mean greater mechanical advantage.
52) A simple machine has a velocity ratio of 10. If its efficiency is 80%, what is its mechanical advantage?
a) 2
b) 5
c) 8
d) 10
Answer: c) 8
Explanation: The mechanical advantage is calculated by multiplying the velocity ratio by the efficiency. Here, it is 10 × 0.8 = 8.
53) What is the primary purpose of a fixed pulley in a pulley system?
a) To increase the force applied
b) To change the direction of the applied force
c) To reduce the distance over which the force is applied
d) To increase the distance over which the force is applied
Answer: b) To change the direction of the applied force
Explanation: The primary purpose of a fixed pulley is to change the direction of the applied force, making it easier to lift loads vertically by applying force horizontally or downwards.
54) What effect does increasing the distance between the fulcrum and the effort in a lever have on the mechanical advantage?
a) Increases the mechanical advantage
b) Decreases the mechanical advantage
c) No change in mechanical advantage
d) The lever becomes less efficient
Answer: a) Increases the mechanical advantage
Explanation: Increasing the distance between the fulcrum and the effort in a lever increases the effort arm, thereby increasing the mechanical advantage.
55) In a lever system, if the mechanical advantage is less than 1, what can be inferred about the lever?
a) It is a Class I lever with a long load arm.
b) It is a Class II lever with a long effort arm.
c) It is a Class III lever with a short effort arm.
d) It is a Class I lever with the fulcrum at one end.
Answer: c) It is a Class III lever with a short effort arm.
Explanation: In a lever system, if the mechanical advantage is less than 1, it typically indicates a Class III lever where the effort arm is shorter than the load arm.
56) What is the primary function of a Class II lever?
a) To change the direction of the applied effort
b) To increase the distance over which the force is applied
c) To act as a speed multiplier
d) To act as a force multiplier
Answer: d) To act as a force multiplier
Explanation: Class II levers, where the load is between the effort and the fulcrum, primarily act as force multipliers, allowing a smaller effort to move a larger load.
57) In a pulley system, what effect does increasing the number of movable pulleys have on the effort required?
a) It increases the effort required.
b) It decreases the effort required.
c) It has no effect on the effort required.
d) It initially decreases then increases the effort required.
Answer: b) It decreases the effort required.
Explanation: Increasing the number of movable pulleys in a pulley system increases the mechanical advantage, thereby decreasing the effort required to lift a load.
58) What does a mechanical advantage greater than 1 indicate in a lever system?
a) The lever acts as a speed multiplier.
b) The lever acts as a force multiplier.
c) The effort is greater than the load.
d) The load is moving faster than the effort.
Answer: b) The lever acts as a force multiplier.
Explanation: A mechanical advantage greater than 1 in a lever system indicates that the lever is acting as a force multiplier, where the output force (load) is greater than the input force (effort).
59) How does the position of the fulcrum in a lever affect its mechanical advantage?
a) Moving it closer to the load increases the mechanical advantage.
b) Moving it closer to the effort increases the mechanical advantage.
c) The position of the fulcrum does not affect mechanical advantage.
d) Moving it to the center always maximizes the mechanical advantage.
Answer: a) Moving it closer to the load increases the mechanical advantage.
Explanation: Moving the fulcrum closer to the load in a lever increases the length of the effort arm relative to the load arm, thereby increasing the mechanical advantage.
60) What is the primary advantage of using a lever in a mechanical system?
a) To reduce the weight of the load
b) To increase or decrease force
c) To stabilize the system
d) To measure the force applied
Answer: b) To increase or decrease force
Explanation: The primary advantage of using a lever in a mechanical system is to increase or decrease the force applied, depending on the class of the lever and the relative lengths of the effort and load arms.
61) In a block and tackle system, if the effort moves four times the distance of the load, what is the system’s velocity ratio?
a) 0.25
b) 1
c) 4
d) 16
Answer: c) 4
Explanation: The velocity ratio in a block and tackle system is the ratio of the distance moved by the effort to the distance moved by the load. If the effort moves four times the distance of the load, the velocity ratio is 4.
62) Which type of lever is typically used for speed amplification rather than force multiplication?
a) Class I lever
b) Class II lever
c) Class III lever
d) Class IV lever
Answer: c) Class III lever
Explanation: Class III levers, where the effort is applied between the fulcrum and the load and the effort arm is shorter than the load arm, are typically used for speed amplification rather than force multiplication.
63) What is the effect of increasing the distance between the fulcrum and the load in a Class I lever?
a) Increases the mechanical advantage
b) Decreases the mechanical advantage
c) No change in mechanical advantage
d) The lever becomes inoperable
Answer: b) Decreases the mechanical advantage
Explanation: In a Class I lever, increasing the distance between the fulcrum and the load decreases the mechanical advantage, as it reduces the length of the effort arm relative to the load arm.
64) A lever system has a load of 50 N and requires an effort of 25 N to balance. What is the mechanical advantage of this lever?
a) 0.5
b) 1
c) 2
d) 4
Answer: c) 2
Explanation: The mechanical advantage is the ratio of the load to the effort. Here, it is 50 N / 25 N = 2.
65) In a pulley system, if the load is lifted by 1 meter, and the effort end of the rope moves 4 meters, what is the velocity ratio?
a) 0.25
b) 1
c) 4
d) 16
Answer: c) 4
Explanation: The velocity ratio is the ratio of the distance moved by the effort to the distance moved by the load. If the effort end moves 4 meters while the load moves 1 meter, the velocity ratio is 4.
66) Which is a characteristic of a Class I lever?
a) The load is between the effort and the fulcrum.
b) The effort is between the load and the fulcrum.
c) The fulcrum is between the effort and the load.
d) The effort and load are on the same side of the fulcrum.
Answer: c) The fulcrum is between the effort and the load.
Explanation: In a Class I lever, the fulcrum is located between the effort and the load. Examples include a seesaw and a crowbar.
67) What is the primary advantage of using a wheelbarrow, a type of Class II lever?
a) To change the direction of the applied effort
b) To increase the speed of lifting
c) To act as a force multiplier
d) To balance weights on either side of the fulcrum
Answer: c) To act as a force multiplier
Explanation: A wheelbarrow, as a Class II lever, primarily acts as a force multiplier. The effort arm being longer than the load arm allows for lifting heavier loads with less effort.
68) If a machine has an efficiency of 50% and a mechanical advantage of 10, what is its velocity ratio?
a) 5
b) 10
c) 20
d) 50
Answer: c) 20
Explanation: The velocity ratio can be calculated as the mechanical advantage divided by the efficiency. Here, it is 10 / 0.5 = 20.
69) Which of the following is an application of a Class III lever?
a) Bottle opener
b) Fishing rod
c) Wheelbarrow
d) Scissors
Answer: b) Fishing rod
Explanation: A fishing rod is an application of a Class III lever, where the effort (applied by the hand) is between the fulcrum (at the hand holding the rod) and the load (at the line end).
70) In a lever, what happens when the length of the effort arm is doubled while keeping the load arm constant?
a) The mechanical advantage is halved.
b) The mechanical advantage is doubled.
c) The mechanical advantage remains unchanged.
d) The lever becomes less efficient.
Answer: b) The mechanical advantage is doubled.
Explanation: Doubling the length of the effort arm while keeping the load arm constant in a lever doubles the mechanical advantage, as it is the ratio of the effort arm to the load arm.
71) In a pulley system with a mechanical advantage of 6, how many supporting strands does the block and tackle have?
a) 3
b) 4
c) 5
d) 6
Answer: d) 6
Explanation: In a block and tackle system, the mechanical advantage is equal to the number of strands supporting the load. Therefore, if the mechanical advantage is 6, there are 6 supporting strands.
72) In which type of lever is the load positioned between the fulcrum and the effort?
a) Class I
b) Class II
c) Class III
d) Class IV
Answer: b) Class II
Explanation: In Class II levers, the load is located between the fulcrum and the effort, often resulting in a mechanical advantage greater than 1.