Does velocity from rotational Ek add to a total velocity of a body?

In summary, the conversation discusses the use of conservation of energy to determine the final velocity of a ball rolling down from an inclined roof. The question is whether the expression for initial velocity should include only translational kinetic energy or both rotational and translational kinetic energy. The expert suggests using conservation of energy to consider all forms of mechanical energy, including both rotational and translational kinetic energy. Despite only being interested in the translational speed of the ball, it is important to use conservation of energy properly to calculate it accurately.
  • #1
rammer
23
0
If we have a ball rolling down from inclined roof that has bottom part at certain height about the ground. I want to know where does the ball land after it leaves the roof. So at this point potential energy is transferred to kinetic (rotational + translational).

My question is: What is the expression I derive an initial velocity from? Is it EK(transl) or EK(transl)+EK(rot)?

I think it should be only EK(transl), because I'm interested only in motion of a centre of mass, right?
BUT, exercises in my book always counts with EK(rot), so I'm pretty confused.

Can you please make it little more clear to me??
 
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  • #2
To find the final velocity of the ball as it leaves the roof you must use conservation of energy. That includes all forms of mechanical energy, which in this case is both rotational and translational KE.

Even though all you care about is the translational speed of the ball, in order to correctly find that speed you must use conservation of energy properly.
 
  • #3
thank you
 

FAQ: Does velocity from rotational Ek add to a total velocity of a body?

How is rotational kinetic energy related to velocity?

Rotational kinetic energy is directly proportional to the square of the velocity. This means that an increase in velocity will result in a larger amount of rotational kinetic energy.

Does the velocity from rotational kinetic energy add to the total velocity of a body?

Yes, the velocity from rotational kinetic energy does add to the total velocity of a body. This is because rotational kinetic energy is a form of kinetic energy, which is a measure of an object's velocity.

Is rotational kinetic energy affected by the mass of a body?

Yes, the rotational kinetic energy of a body is affected by its mass. A larger mass will result in a larger amount of rotational kinetic energy, assuming the velocity remains constant.

Can the direction of rotational kinetic energy change?

Yes, the direction of rotational kinetic energy can change. This is because rotational kinetic energy is dependent on the rotation of an object, and the direction of rotation can change if an external force acts on the object.

How is rotational kinetic energy different from linear kinetic energy?

Rotational kinetic energy is a type of kinetic energy that is associated with an object's rotation, while linear kinetic energy is associated with an object's linear motion. They are calculated using different formulas and have different units of measurement.

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