Question

40 POINTS EASY

Determine the mechanical energy of this object : a 1-kg ball rolls on the ground at 2 m/s.

A. The ball is on the ground, so the mechanical energy is 0
B. 2J
C. 1J
D. 4J

Answer 1

We know, Mechanical Energy = K.E. + P.E.
As ball is at ground, P.E. would be zero. But as it is in motion, it must have some K.E. and that is:

K.E. = 1/2 mv²
K.E. = 1/2 * 1 * 2²
K.E. = 4/2
K.E. = 2 J

In short, Your Answer would be Option B

Hope this helps!