Question

Two stones are thrown from the top of a tower, one straight down with an initial speed u and the second straight up with the same speed u. When the two stones hit the ground, they will have speeds in the ratio

Choose the correct answer:

2:3
2:1
1:2
1:1

Answer 1

they have same initial velocity so the ratio will 1:1

Answer 2

Answer:

Explanation:

In case of stone thrown downwards, initial velocity,u=u

So, using equation v^2

−u^2=2aS,

here, u=u,v=0,a=a,S=Distance

So, final equation=u^2=2aS......(1)

Again, for stone thrown upwards, initial velocity,u=−u

So, using equation v^2−u^2=2aS,

here, u=−u,v=0,a=a,S=Distance=S

So, final equation=u^2

=2aS.......(2)

Dividing (1) by 2, we get ratio of 1:1

In both the cases,(u is positive or negative)u^2

is positive.