Question

4. A 20-kg ball is thrown upward with a
speed of 4 ms-¹
(a) Find its potential energy when
reaches the highest point.
(b) Calculate the maximum height
reaches​

Answer 1

Answer:

16000J and 80m

Explanation:

From third equation of motion,

v^2 -u^2=2gs

here v=0 as velocity becomes zero at topmost point. g =-10 as it is acting against morion of ball.

-40×40=-2×10×s

s=80 m

required P.E= mgh=20×10×80=16000J