Answer:
6200 J
Explanation:
Momentum is conserved.
mā uā + mā uā = mā vā + mā vā
The car is initially stationary. Ā The truck and car stick together after the collision, so they have the same final velocity. Ā Therefore:
mā uā = (mā + mā) v
Solving for the truck's initial velocity:
(2700 kg) u = (2700 kg + 1000 kg) (3 m/s)
u = 4.11 m/s
The change in kinetic energy is therefore:
ĪKE = Ā½ (mā + mā) vĀ² ā Ā½ mā uĀ²
ĪKE = Ā½ (2700 kg + 1000 kg) (3 m/s)Ā² ā Ā½ (2700 kg) (4.11 m/s)Ā²
ĪKE = -6200 J
6200 J of kinetic energy is "lost".
