Question

The diagram below shows a claw hammer used to remove a nail.

1. To which class of lever does it belong?
2. Give one more example of the same class of lever mentioned by you in (i) for which the mechanical advantage is greater than one.
3. Two bodies A and B have masses in the ratio 5 : 1 and their kinetic energies are in the ratio 125 : 9. Find the ratio of their velocities.

Answer 1

(a) The claw hammer acts as a first-class lever because the fulcrum lies between the effort and the load.

(b) One more example is a crowbar used to lift a load. Its mechanical advantage can be greater than one when the effort arm is longer than the load arm.

(c) Given: m_A : m_B = 5 : 1

K_A : K_B = 125 : 9

Using, `K = 1/2 m v^2`

`K_A/K_B = (m_A v^2A)/(m_B v^2B)`

`125/9 = (5 v^2 A)/(v^2B)`

`(v^2A)/(v^2B) = 25/9`

`v_A/v_B = 5/3`

v_A : v_B = 5 : 3