# Gravitationl Potential energy

#### gansta344u

1. Homework Statement
A 2.35 kg ball is attached to a ceiling by a
1.92 m long string. The height of the room is
5.92 m .
The acceleration of gravity is 9.8 m/s2 .
What is the gravitational potential energy
associated with the ball relative to the ceiling?
Answer in units of J

What is its gravitational potential energy rel-
ative to the floor? Answer in units of J.

What is its gravitational potential energy rel-
ative to a point at the same elevation as the
ball? Answer in units of J.

2. Homework Equations
PE=mgh

3. The Attempt at a Solution
I TRIED TO USE THE EQUATION BUT WHEN I PUT IT IN IT WAS WRONG MAYBE I AM CALCULATING WRONG PLEASE HELP MAYBE IF U CAN PROVIDE A MODIFIED EQUATION OR EVEN A SIMPLE ONE THAT WOULD HELP A LOT!

Related Introductory Physics Homework Help News on Phys.org

#### Doc Al

Mentor
2. Homework Equations
PE=mgh
Perhaps if you thought of the equation as PE = mgy, where y is the vertical position with respect to your reference point, you may understand it better.

For example, if you choose the ceiling as your reference, that means that y = 0 at the ceiling. What's the y value of the ball in that case?

#### Doc Al

Mentor
Hint: Pay attention to the sign of your answer.

#### gansta344u

thanks a lot it helped a lot especially the last part, it worked.

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving