A carpenter on top of a roof of 20.0m high dropped a hammer of mass 1.5 kg and it fell directly to the ground. the kinetic energy of the hammer just before hitting the ground is?[g = 10 ms-2]
-
A.
600 J -
B.
150J -
C.
300 J -
D.
450 J
Correct Answer: Option C
Explanation
K e just before hitting the gound
= P e at the maximum height (conservation of mechanical energy)
K e = P e = mgh = 1.5 x 10 x 20
= 300 J