Question

A60kg mass initially at rest explodes into two fragments. The

20kg fragment moves east at 30m/s. What is the velocity of
the 40kg fragment?

Answer 1

After an explosion, the 40kg fragment moves in the opposite direction of the 20kg fragment with a velocity of 15 m/s, which is west.

Step-by-step explanation:

When an object explodes, conservation of momentum applies. The total momentum before the explosion is zero as all the fragments are at rest. After the explosion, the total momentum is still zero as the momentum of one fragment is equal and opposite to the momentum of the other fragment.

Let's call the 20kg fragment A and the 40kg fragment B. The velocity of fragment A is east at 30 m/s, and we want to find the velocity of fragment B.

The momentum of fragment A is:

Pa = mA * vA = 20 kg * 30 m/s = 600 kg*m/s

The momentum of fragment B is:

Pb = mB * vB = 40 kg * vB

According to conservation of momentum:

Pa + Pb = 0

600 kg*m/s + 40 kg * vB = 0

vB = -15 m/s (west)

The negative sign indicates that fragment B moves in the opposite direction to fragment A, which is west. Therefore, the velocity of fragment B is west at 15 m/s.