Question

A child drops a ball from a height of 5 metre assume that its velocity increases uniformly at a rate of 10 metre per second .Find (1)the velocity with which the ball strikes the ground second. (2) the time taken by the ball to reach the ground ​

Answer 1

Answer:

v = 10m/s, t= 1s

Explanation:

h = distance covered = 5 m

Rate of increase (change) in velocity = a (acceleration) = (10 m/s) per second

                                                       or, g (acceleration due to gravity) = 10 m/s²

u = initial velocity = 0 m/s (as the ball is just dropped from the top, and not thrown using any force)

Using equation of downward motion,

v² = u² + 2gh

v² = 0² + 2(10)(5)

v² = 0 + 100

   v = $\sqrt{100\\}$

   v = ±10

Since velocity cannot be negative, v = 10m/s

Using equation of downvard motion,

v = u + gt

10 = 0 + 10t

10 = 10t

  t = 1 second