Question

A 1.2-kg object moving at 5.0 m/s collides with and sticks to a 4.8-kg object initially at rest. What is the amount of kinetic energy lost by the system during this collision?

Answer 1

Answer:

-15J

Explanation:

Step one:

given data

m1= 1.2kg

v1= 5 m/s

m2= 4.8kg

v2= 0 m/s

Required

The kinetic energy lost

Step two:

The kinetic energy before impact is KE1

$KE1= 1/2mv^2\\\\KE1= 1/2*1.2*5^2\\\\KE1= 15J$

KE after impact is KE2

$KE2= 1/2*(m1+m2)v2\\\\KE2= 1/2*(6)0\\\\KE2= 0 J$

The loss in Kinetic energy is

Loss in KE= KE2-KE1

Loss in KE= 0-15

Loss in KE= -15J