Question

A ball town down vertically with an initial speed of 20 m/s from. a height of 60 m. Find
(i) its speed just before it strikes ithe ground.
ii) how long it takes for the ball
to reach the ground.​

Answer 1

Step-by-step explanation:

The solution is pretty simple and you can get it by working on equations of motion.

You throw a ball vertically upwards and the ball will travel a distance of ‘h’ (vertically) before attaining zero velocity. Then it will continue its journey, falling with constant acceleration.

The velocity at point-1 and point-3 will be the same.

Therefore, u(1) = u(2) = u (which is to be calculated or found).

We have,

v = u + (g * t)

v = u + (10 m/sq. sec * 10 sec)

v = u + 100 ………………………..(EQUATION 1)

And,

Substituting the value of v (from eqn-1) in above,

Substituting g = 10 m/sq. sec, and s = 80 m,

You will have the value of initial velocity (u) as 42 m/s.

Hopefully, this helps.