Answer:
17,600 J
Explanation:
From the problem statement, the increase in the internal energy is equal to one third of the sledgehammer's initial kinetic energy. The kinetic energy of an object is equal to half its mass times the square of its speed. By finding the sledgehammer's kinetic energy, we can find the increase in internal energy.
The hammer's kinetic energy is:
KE = ½ mv²
KE = ½ (2.50 kg) (65.0 m/s)²
KE = 52,812.5 J
The increase in internal energy is:
ΔE = ⅓ KE
ΔE = ⅓ (52,812.5 J)
ΔE = 17,600 J
