Mechanical Energy: A Q&A on I, II, III, IV

[TheHamburgler1]

So I have a quick question that I got in my physics class and I'm not to informed on Mechanical energy so if you could help me out that would be great:

Which of following is/are true regarding the principle of mechanical energy?
I. An object moves uphill with a decreasing speed
II. An object moves downhill with an increasing speed
III. An object moves downhill with a decreasing speed
IV. An object moves downhill with a constant speed

A) I only
B) I and II
C) I and III
D) I and IV
E) II only


could i get an answer and an explanation?? thanks

 

[billiards]

You should be able to figure this out intuitively by imagining rooling a ball up a hill first, will it speed up or slow down as it gets further up hill? And rolling a ball down the hill, will it speed up or slow down?

 

[QuantumCrash]

What have you worked out so far?

If you really are that stuck, the Mechanical Energy in this case is Kinetic Energy and Gravitational Potential Energy. Work out the change, and then use KE to find the answer.