Question

A rock with mass of 5.0 kg is carried up a small hill 10 meters high. How much work had to be done in carrying the rock up hill?

W =

490 J

4900 J

245 J

impossible to tell because velocity not given

Answer 1

The work done will be equivalent to the potential energy gained by the rock. Thus:
Work = P.E = mgh
Work = 5 x 9.81 x 10
Work = 490.5 J

The first option is correct.

Answer 2

m = 5 kg,
h = 10 m,
g = 9.8 m/s²
-----------------
Work : W = m · g · h
W = 5 · 9.8 · 10 = 490 J
Answer: A ) 490 J