Question

A boy sees a ball going up then coming down through a windows of 2m high .If the total time the ball in sight 1s ,the height above the window that the ball rises is

Answer 1

Given: A ball going up then coming down through a windows of 2 m high, total time the ball in sight 1 s.

To find: The height above the window that the ball rises?

Solution:

• Now we have given the window of 2 m high and ball in sight as 1 s.

• The formula for distance is: s = ut + 1/2 x at²

• Here a = g and u = speed when the ball passes the bottom of the window

• The time for travelling in one direction will be = 1/2 sec

• So putting these values in formula, we get:

         2 = u/2 + 1/2 x 9.8 x (1/2)²

         2 = u/2 + 9.8/8

         2 = u/2 + 1.225

         u/2 = 2 - 1.225

         u/2 = 0.775

         u = 1.55 m/s

• So total height the ball rises from bottom of the window will be:

         s1 = (1.55)² / (2 x 9.8)

         s1 = 2.4025 / 19.6

         s1 = 0.12257 m

Answer:

        So the height above the window that the ball rises is 0.12257 m.