Gravitational Potential Energy

[tatkh]

Hello!

I have a question regarding GPE. Can you please help me with this question (attached) and why it is the case? I am very confused with what happens to GPE as its height is increased.

Thank you

[talitha_h]

Hello!

I have a question regarding GPE. Can you please help me with this question (attached) and why it is the case? I am very confused with what happens to GPE as its height is increased.

Thank you

the answer is c) it became more positive because although GPE is a negative value, as you move away from the Earth you are moving towards zero (which is an infinite distance away) and hence, you are giving the space station a greater potential energy. Think - as you lift an object up you are giving it more GPE and it therefore is becoming more positive

[impulsebro89]

As your height increases, you gain GPE (just imagine lifting an apple from your table - it gains GPE which it previously did not have when it was on the table). Because GPE is 0 when it's at an infinite distance from a planet's gravitational field, when you move something like the ISS away from the Earth it gains GPE.

I find it really helpful to think of a number line: If GPE is a negative value, its position starts at the left of the 'zero' mark on the number line. Now as you gain GPE, you move towards the right on a number plane (i.e. move towards zero). You're still going to have a negative value, but it becomes smaller and smaller as you go towards zero (-5, -4, -3, -2....0)

So the answer is C because the value of the GPE becomes 'more positive', even though the GPE is still negative

Hope this helps!