Question

What is the mechanical energy of the cart on the right at position A. The

cart is not in motion. (height=15 m, mass = 12 kg, gravity = 10 m/s2)?

Answer 1

1800

Explanation:

P.E. =m.g.h = 12x10x15 = 1800 Joules

K.E/ = 1/2 mv2 = 1/2x12x02 = 0

P.E = 1800 | K.E. 0

M.E. = 1800 + 0 = 1800 Joules

Answer 2

1800 J

Explanation:

At point A when the cart is not in motion, it only has potential energy.

We know that potential energy is given by mgh where m is the mass of the cart, g is acceleration due to gravity and h is the height.

Substituting 12 kg for m, 10 m/s2 for g and 15 m for h then

PE= 12*10*15=1800 J