Question

From the top of a tower two stones, whose masses are in the ratio 1:2
are thrown one straight up with an initial speed 'u' and the second
straight down with the same speed 'u'. Then, neglecting air resistance
(A) the heavier stone hits the ground with a higher speed
(B) the lighter stone hits the ground with a higher speed
(C) both the stones will have the same speed when they hit the ground
(D) the speed can't be determined with the given data​

Answer 1

☆ Answer

--> Both the stones will have the same speed when they hit the ground

first stone thrown straight up with velocity u upward and  gravitation acceleration acts downwards. 

so first particle goes up to some height when its velocity becomes zero

and then this particle gets free fall. now when the particle goes down at level of top of tower it velocity becomes u downward and gravitation acceleration also in downward direction.

by using newtons law of motion. for first particle

v2=u2+2as(a=g;s=hheightoftower)v12=u2+2gh

same as for second particle

initial velocity is u downward and g downward

v2=u2+2as(a=g;s=hheightoftower)v22=u2+2gh

So both the stones have same speed at the ground level

hence option C is correct