Question

Just need to confirm an answer

A ball of mass 0.2 kg is kicked straight up from ground level. Ignoring air resistance, its gravitational potential energy as it reaches its maximum
height is 10 J. The initial speed with which the ball was kicked is most nearly
(A) 20 m/s (B) 10 m/s (C) 5 m/s (D) 1 m/s

Answer 1

B

Step-by-step explanation:

Remark

If, when it reaches its maximum height where the PE is the greatest, that the maximum energy is when the ball is first kicked. That would mean its starting energy is 10 Joules.

Formula

KE = 1/2 m v^2

Givens

KE = 10 J

m = 0.2 kg

v = ?

Solution

10 = 1/2 * 0.2 * v^2

10 * 2 = 0.2 * v^2

20 = 0.2 * v^2

20/0.2 = v^2

100 = v^2

v = 10 m/s