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turning of objects

Hi everyone, I'm just doing some learning and was wondering something

Why is it that objects with a greater mass turn more slowly, is it due to their moment of inertia?

Reply 1

zaback21

Original post by Kolasinac138

Hi everyone, I'm just doing some learning and was wondering something

Why is it that objects with a greater mass turn more slowly, is it due to their moment of inertia?

It depends on what moment of inertia you are talking about.

Yes if its due to mass moment of inertia.

It depends if its 2nd moment of inertia. Then it depends on the shape of the object.

To answer your question: F=ma. So, more mass means more force is required. Or for the same force, more mass means, less acceleration or turning more slowly (angular acceleration).

Reply 2

uberteknik

Original post by Kolasinac138

Hi everyone, I'm just doing some learning and was wondering something

Why is it that objects with a greater mass turn more slowly, is it due to their moment of inertia?

F=ma

Your question only makes sense if the forces acting on the mass remain constant:

Energy conservation laws cannot be broken.

To turn, the object is constantly changing direction. i.e. accelerating.

The faster the object turns, the more force is required for it to do so.
Similarly, if the mass of the object increases, then once again, the more force is needed to accelerate.

If the forces acting are held constant, but the mass has increased, then to preserve the energy conservation laws, the acceleration must reduce.

Reply 3

Stonebridge

Original post by Kolasinac138

Hi everyone, I'm just doing some learning and was wondering something

Why is it that objects with a greater mass turn more slowly, is it due to their moment of inertia?

Do you mean spin more slowly? That depends on moment of inertia.
Moment of inertia depends not only on the mass of the object, but also on the distribution of that mass. This in tern depends on shape and density.

Reply 4

Kolasinac138

I did mean spin, sorry. I have a mass of 2 kg suspended from an elastic rubber band on a clamp and am trying to see why it spins more slowly when I add more mass to it.

Reply 5

Stonebridge

Original post by Kolasinac138

I did mean spin, sorry. I have a mass of 2 kg suspended from an elastic rubber band on a clamp and am trying to see why it spins more slowly when I add more mass to it.

The question is too vague.
How are you making it spin?
How are you measuring the "speed" at which it spins?
It this constant rotation in one direction or are you making it oscillate?
What is the shape of the mass?
How are you adding more mass? (Where? On top? On the outside edge?)

Reply 6

Kolasinac138

Original post by Stonebridge

I'm touching it with my hand.

I'm not measuring the speed but the time period of one oscillation.

The rotation is constant in two directions - it's a pendulum essentially. Oscillation.

The mass essentially looks like so without the spring(rubber band) and more mass ( the mass is in the 5 gram blocks which are added on top)