Verified answer

"relative to the shelf" means that the shelf is at the origin, where h = 0

therefore, the ball is at height: h = -0.610

Eg = mgh

Eg = - 43.7 J

U=MGH or W=FxD both work for PEG (Potential energy gravitational)

Assuming gravity is constant.

Alternatively

U=-g m1m2/r

Find magnitude in newtons law of gravitation

Be careful the answer is NOT negative. If height is 0 you multiply Mass and gravity by 0 you get 0. The height of 0 is key. Commutative rule of multiplication applies here.

Only the first 2 replies and mine are correct.

PE = mgh

m= mass of object

g = acceleration of gravity

h = hieght of object from ground (or other surface)

If the ball were on the shelf.

PE = 7.30kg*9.8m/s*0.610m = (do the math) Joules

But the ball is on the ground so it has no PE because h = 0.

Considering the equation:

PE = mgh, where 'PE' is potential energy, 'm' is mass, 'g' is gravitational pull, and 'h' is the altitude, all you really have to do is plug in.

m=7.30

g=9.8

h=-0.610 (negative because the shelf is ABOVE the position of the ball)

PE = (7.3)(9.8)(.61)

PE = -43.68 Joules

The force of gravity in this case is positive because of the acceleration vector you're looking at.

The ball on the shelf has PE of m g h = 7.3*9.8*0.61 = 43.64 J more than what it would on the floor.

Usually you only worry about changes in PE from one level to another.

Height of the ball relative to the shelf is h = - 0.610 m

P.E. = Mgh = 7.30 * (9.81) (-0.610) = - 43.68 J

Ep=Wh=mgh=7.3 x 9.8 x 0.61=43.64joules