A lift is descending with an acceleration a. A person standing in it drops a book. The acceleration of book relative to floor of lift will be (take acceleration due to gravity g)
A) g
B) a
C) g - a
D) g + a

Question

A lift is descending with an acceleration a. A person standing in it drops a book. The acceleration of book relative to floor of lift will be (take acceleration due to gravity g)
A) g 
B) a
C) g - a 
D) g + a

theeric · Answer

Hi! Do you have any ideas?

theeric · Answer

Hint:  what causes acceleration?

samigupta8 · Answer

acceleration is caused by change in velocity

theeric · Answer

Acceleration is a change in velocity! And it is also caused by a force! But, I thought of a better way to look at it.

When the person let's go of the book, it is in freefall. So, what is the acceleration of an object in freefall?

samigupta8 · Answer

$$9.8m/s^{2}$$

theeric · Answer

And what variable do you use for that? THAT is your answer! :)