Question

A stone thrown vertically up from the top of a tower with a velocity of 20m/s reaches the ground in 6s.find the height of the tower​

Answer 1

Answer:

120 metre

Explanation:

height s = velocity × time =20× 6 = 120

Answer 2

Thrown vertically up with 20 m/s from top of the tower.

It reaches the ground in 6 seconds.

As the stone is thrown upward it will reach its highest point and at that point its velocity will be zero.

Let it reaches highest point at time "t".

Now,

u = 20 m/s.

v = 0 m/s.

a = - 10 m/s^2.

t = ?.

From first kinematics equation.

Substituting the values.

Now for free fall the time taken is

t' = 6 - 2

t' = 4 seconds.

u = 0 m/s.

a = 10 m/s^2.

S = H(Height of tower)

From second kinematic equation.

Substituting the values.

So,the height of tower is 80 meters