Question

A body is projected vertically with a speed of 20 m/s in a region where g= 10 m/s 2 . The distance traveled in 3 seconds is

Answer 1

We know that a body projected vertically upward takes ug second to reach to the highest point.

Here u=20ms−1,a=−g=−10ms−2, therefore the body attaining maximum height, the body retraces its path.

Since the path is reversed after 2s, the relation

s=ut+12at2 with t=3 will not give the distance travelled.

This formula will give the displacement of the body from the ground.

Thus,s=20(3)−12(10)(3)2=15m

The maximum height is given by s(max) =20(2)0−12(10)(2)2=20m

Hence the distance covered by the body in 3 s is given by 20+(20−15)=25m

Hópe it helps you

Answer 2

We know that a body projected vertically upward takes ug second to reach to the highest point.

Here u=20ms−1,a=−g=−10ms−2, therefore the body attaining maximum height, the body retraces its path.

Since the path is reversed after 2s, the relation

s=ut+12at2 with t=3 will not give the distance travelled.

This formula will give the displacement of the body from the ground.

Thus,s=20(3)−12(10)(3)2=15m

HOPE IT HELPS !!!