Question

A block of mass 2 kg is kept inside a lift. Lift starts moving downward with an acceleration of a = 12 m/s2 Height of the lift
is 4m. Time after which block will strike roof of the lift is
​

Answer 1

Answer:Because, the elevator is moving downward with an acceleration 12m/s  

2

(>g), the body gets separated. So, body moves with acceleration g=10m/s  

2

(freely falling body) and the elevator move with the acceleration 12m/s  

2

 

Now, the block has accelerationg=10m/s  

2

 

u=0

t=0.2sec

So, the distance traveled by the block is given by;

∴s=ut+  

2

1

​  

at  

2

 

s=0+  

2

1

​  

×10×0.2  

2

=5×0.04=20cm

Explanation:if you have another question this answer will be helpful to you