Question

A boy stands at a place on a bridge which is 5 m above water
surface. He throws a stone vertically upwards with a speed of 20
ms!
(a) How high above the bridge will the stone rise?
(b) After how many seconds from the start will the stone hit
water surface?
(Take g - 10 m )​

Answer 1

Answer:

5.09 seconds

Explanation:

The time of rise from the bridge = 2.04 seconds. The time of fall from maximum height to bridge = 2.04 seconds.

The time of fall from the bridge to water is t^2 = 2d/g where d = 5 m and g = 9.8 m/s^2. It is 1.02 s^2. Its square root is 1.01 seconds. Adding the 3 solved time we get the total time of (2.04 + 2.04 + 1.01) s = 5.09 seconds.

It will take 5.09 seconds for the stone from its starting position to the water surface.

Answer 2

foll... me and like me to get the answer