Posted by **Kathrine** on Wednesday, December 17, 2008 at 7:58pm.

How is it possible for gravitational potential energy to be negative?

I Googled the answer, but all I could understand was that if the PE was zero at infinity as you move toward an object with gravity the KE must be positive because KE is the energy of motion so the the PE must be negative to equal a total of zero. Is this right? Or am I way off the mark?

- Physics -
**bobpursley**, Wednesday, December 17, 2008 at 8:01pm
PE is always to a reference. It is zero at infinity. But we commonly set some place (say ground level) and measure GPE in relation to that plane. Negative GPE means energy has to be given to get it back to zero. Example: refernce level is at 12 feet above ground. Below that, GPE is negative.

- Physics -
**Kathrine**, Wednesday, December 17, 2008 at 8:13pm
Okay, so using the ground level for your reference point if you went under the crust the GPE must be negative for the total energy to remain zero?

I think I get it! Thanks a lot!

- Physics -
**bobpursley**, Wednesday, December 17, 2008 at 8:13pm
That is it.

- fgox oilx -
**fgox oilx**, Saturday, January 17, 2009 at 2:45am
cbnewmzja kzjqtfg revk yqpinmhla bjenp vokjmn lfkmvpt

## Answer This Question

## Related Questions

- physics - A 0.720 kg snowball is fired from a cliff 8.10 m high. The snowball's ...
- Physics - what is the gravitational potential energy at the centre of the earth...
- Physics - what is the gravitational potential energy at the centre of the earth...
- physics - ok i need help on this other question please A 56.0 kg skier is at the...
- Physical Science - If potential energy of an electron in ground state is -13.6 ...
- Physics - Point charges Q1 ,Q2 , and Q3 reside on three corners of a square ...
- College Physics - A 22.9-kg child is on a swing attached to ropes that are L = 1...
- Science(Stuff to do like with magnets!) - 1. A positively charged test object is...
- Physics - Consider the gravitational potential, kinetic, and total mechanical ...
- physics - i need some help wih this, thanks!! Blocks A and B are moving toward ...

More Related Questions