Question

Which class of lever found in the human body is being used by a boy:
(i) When he holds a load on the palm of his hand.
(ii) When he raises the weight of his body on his toes?

Answer 1

Hint: In this question you have to know classification of lever and accordingly the location of output force, input force and fulcrum.

Complete step by step answer:
(i) Class 3rd lever is used when he holds a load on the palm of his hand.
(ii) Class 2nd lever is used when he raises the weight of his body on his toes.
Explanation:
Now, we will study in detail about the three classes of lever
Class of lever:
1st Class lever: If the fulcrum is in between the output force and input force as in seesaw.
2nd Class lever: The output force is in between the output force is in between the fulcrum and input force.
3rd Class lever: Input force is in between the output force and fulcrum

When the boy holds load on the palm of his hand, it is a 3rd class lever as the input force that is load acts from the palm of hands not fingers while the fulcrum on the other end as shown in figure.
When a boy raises the weight of his body on his toes, it is an example of class 2 lever as the input force is applied by the front of the toes.

Note:
So, according to these classes of lever we find the solution of the question.The input force is the place where the load is acting while the output is the effect.