# Loop the Loop

Compared to an object that does not roll, but instead slides without friction, should a rolling object be released from the same,a greater, or a lesser height in order just barely to complete the loop the loop?

A The rolling object should be released from a greater height.
B The rolling object should be released from a lesser height.
C The rolling object should be released from exactly the same height.
D The answer depends on the moment of inertia of the rolling object.

I think the answer depends on the moment of inertia of the rolling object cause if it had a large inertia, it would be harder for it to accelerate.

Could somebody just verify my answer?

Thanks

Päällikkö
Homework Helper
With conservation of energy principle, form the required equation.

I don't completely understand what you're trying to say

daniel_i_l
Gold Member
How much of it's original potential energy does each case use to do the loop? The one that uses less need more energy you start with.

Päällikkö
Homework Helper
daniel_i_l said:
How much of it's original potential energy does each case use to do the loop? The one that uses less need more energy you start with.
I think this message could easily be misunderstood. No energy is actually "used", the total energy remains constant, just the form changes.

To the original poster:
Well... If the object isn't rolling, what must the release height be for it to loop the loop (in terms of the loop's radius, R)? The easiest way to solve this is with the conservation of energy principle.

Now, can you form the equation for a rolling object (it's slightly different, think rotational energy) and solve for h?

Last edited:
daniel_i_l
Gold Member
Sorry for the poor phrasing. I meant that if the ball spins, less potential energy is turned into kinetic energy.