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Gravitational Potential question

at.midnight

How do you solve both parts i) and ii) of this question?

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Reply 1

MacsenT

Original post by at.midnight

How do you solve both parts i) and ii) of this question?

if you integrate the force due to gravity with respect to r you get the potential energy, gravitational potential is that potential energy per unit mass, let me know if that doesn't help enough

Reply 2

username4407536

Um I think for A level the result for gravitational potential is used without proof:

gravitational potential = -GM/r

Reply 3

MacsenT

Original post by golgiapparatus31

Um I think for A level the result for gravitational potential is used without proof:

gravitational potential = -GM/r

haha trust me ive only done AS physics but practicing deriving formulas using calculus makes understanding them so much more easy

Reply 4

username4407536

Original post by MacsenT

haha trust me ive only done AS physics but practicing deriving formulas using calculus makes understanding them so much more easy

Okay but would you derive it in the exam? I think not because that's not useful use of the time allocated to do the exam...

I agree that deriving formulas makes understanding them a lot easier though, but I won't do that when answering questions xD

Reply 5

MacsenT

nah you wouldn't do it in an exam, but as soon as you give people variable forces they fall to pieces, better to be confident with it before hand

Reply 6

username4407536

Original post by MacsenT

nah you wouldn't do it in an exam, but as soon as you give people variable forces they fall to pieces, better to be confident with it before hand

What do you mean? If variable force is given in the exam it will probably be solvable using energy method, or studied in class e.g Hooke's law. It will never involve calculus

Reply 7

MacsenT

Original post by golgiapparatus31

What do you mean? If variable force is given in the exam it will probably be solvable using energy method, or studied in class e.g Hooke's law. It will never involve calculus

nah they wont give it in the exam, if they do it would just be something like comparing initial Ek and Ep with final Ek and Ep and saying oh well drag's done a bit of work then, i just mean more in physics in general i dont think you should just be taught to pass the exam