You toss a rock of mass mm vertically upward. Air resistance can be neglected. The rock reaches a maximum height hh above your hand. What is the speed of the rock when it is at height h/4h/4?

The speed of the rock when it is at height h/4 is .

Explanation:

At maximum height the final velocity of the rock is equal to 0. Let u is the initial velocity of the rock. Using the conservation of energy to find it as :

.......(1)

We need to find the speed of the rock when it is at height h/4. Let v' is the speed. Using 3rd equation of motion as :

here a = -g and s = h/4

Using equation (1) :

So, the speed of the rock when it is at height h/4 is . Hence, this is the required solution.

Explanation:

We are given that

Mass of rock=m

We have to find the speed of the rock when it is at height h/4

When the rock reaches at maximum height then speed,v=0

Let u be the initial velocity of rock=u

We know that

When h=h/4

Substitute

m/s

if they have a finite resultant