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

588 J

Step-by-step 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* 9.8* 10`

v = 14 m/s

The formula for the kinetic energy is given by

`K=(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