Question

A 6.0 kg ball is dropped from a 10-m height. Its kinetic energy, just before it hits the ground is : 588 J
392 J
280 J
140 J
882 J

Answer 1

Answer:

588 J

Explanation:

mass of ball, m = 6 kg

Height from it dropped, h = 10 m

initial velocity, u = 0

acceleration due to gravity, g = 9.8 m/s^2

Let it hits the ground with velocity v.

Use third equation of motion

$v^{2} = u^{2}+2as$

$v^{2}=0^{2}+2\times 9.8\times 10$

v = 14 m/s

The formula for the kinetic energy is given by

$K=\frac{1}{2}mv^{2}$

where, m is the mass of the ball and v be the velocity of the ball as it hits the ground

K = 0.5 x 6 x 14 x 14

K = 588 J