Class 2 Lever

Q.

Draw a labelled diagram of a class II lever. Give one example of such a lever.

Q.

Draw a diagram of a lever which is always used as a force multiplier. How is the effort arm related to the load arm in such a lever ?

Q.

Classify the following as levers of the first, second, and third-order.

(a) Forceps

(b) Lock and key

(c) Pliers

(d) A fishing rod

(e) A nut cracker

(f) See-saw

Q.

A lock and key is an example of lever of first order.

1. True
2. False

Q.

The figure below shows a wheel barrow of mass 15 kg carrying a load of 30kgf with its centre of gravity at A. The points B and C are the centre of wheel and tip of the handle such that the horizontal distance AB= 20 cm and Ac = 40 cm.

Find : (a) the load arm, (b) the effort arm, (c) the mechanical advantage, and (d) the minimum effort required to keep the leg just off the ground.

Q.

In fig shows a lemon crusher.

(a) In the diagram, mark the position of the fulcrum F and the line of action of load L and effort E.

(b) Name the class of lever.

Q.

Class II levers are designed to have :

(a) M.A = V. R. (b) M.A > V. R.

(c) M.A. > 1 (d) M. A. < 1

Q.

The diagram below shows a rod lifting a stone.

(a) Mark position of fulcrum F and draw arrows to show the directions of load L and effort E . (b) What class of lever is the rod ? (c) Give one more example of the same class of lever stated in part (b).

Q. ntThere are two cases. In the first case a spring (spring constant k) is pulled by two equal and opposite forces F at both ends and in second case one end of spring is fixed to a rigid support and other end is pulled by a force F. Extensions (x) in the string will ben

Q.

Explain why the mechanical advantage of a class II lever is always more than 1.

Q.

Which type of lever has a mechanical advantage always more than 1 ? Give reason with one example. What change can be made in this lever to increase its mechanical advantage ?

Q.

A wheel barrow is an example of a lever of the first order.

1. True
2. False

Q.

A beam balance is a lever of

1. class-I

2. class-II

3. class-III

4. None of these

Q.

A screw jack acts as a ____ multiplier.

Q.

Write the relation between the mechanical advantage (MA) and velocity ratio (VR) of an ideal machine.

Q.

In the following pulley system the utility of the fixed pulley is to

1. To increase MA

2. To increase VR

3. To decrease tension

4. To reverse the direction of Effort in a convenient direction

Q.

List the daily life situations where you use simple machines

Place: In Classroom

Situation:

Simple Machine:

Q.

The figure below shows a human hand. Mark the positions of load, effort, and fulcrum in the diagram. Name the type of lever hand.

Q.

State the class of levers and the relative positions of load, effort, and fulcrum in the following cases:

a)Bottle opener

b)Sugar tongs

Q. In a second order lever, the effort arm is always _____ than load arm.

1. Depends on the weight used
2. Smaller
3. Equal
4. Greater

Q.

In fig below shows a lever in use.

(a) To which class of lever does it belong?

(b) If FA = 80 cm, AB = 20 cm, find its mechanical advantage.

(c) Calculate the value of E.

Q.

State the kind of lever which always has the Mechanical Advantage (MA) less than 1.

1. Class I lever

2. Both class I and class II lever

3. Class II lever

4. Class III lever

Q.

The diagram shows a pulley system which lifts a load of 1000N against gravity through a height 2m. Calculate the displacement of the effort and the efficiency of the system is 100% then calculate the tension force in the tackle.

1. 4 m, 500 N

2. 4 m, 2000 N

3. 1 m, 500 N

4. 1 m, 2000 N

Q.

A lever of length 9 cm has its load arm 5 cm long and the effort arm is 9 cm long. (a) To which class does it belong ? (b) Draw diagram of the lever showing the position of fulcrum F and directions of both the load L and effort E. (c) What is the mechanical advantage and velocity ratio if the efficiency is $100\%$ (d) What will be the mechanical advantage and velocity ratio if the efficiency becomes $50\%$ ?

Q. Assertion :All surfaces shown in figure are smooth. Block A comes down along the wedge B. Work done by normal reaction (between A and B) on B is positive while on A it is negative. Reason: Angle between normal reaction and net displacement of A is greater than ${90}^o$ while between normal reaction and net displacement of B is less than ${90}^o$.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q.

A lever of second-order can be used as vegetable cutter

1. True
2. False

Q.

Which one of the following is a $ClassIIlevers$?

1. 

2. 

3. 

4. 

Q. Which class of lever has the load located between the effort and the fulcrum?

1. Class I
2. Class III
3. Class II
4. Both A and B