Simple rotational motion problem

In summary, the conversation discusses two identical merry-go-rounds rotating at the same speed, one with riding children and the other nearly empty. The question is posed whether the one with people will take longer to stop when both cut off their motors and coast to a stop, assuming equal friction. The conclusion is that the one with people will take longer to stop due to its larger moment of inertia and therefore requiring more force to stop.
  • #1
kirby27
32
0
Two identical merry-go-rounds are rotating at the same speed. One is crowded with riding children; the other is nearly empty.

If both merry-go-rounds cut off their motors at the same time and coast to a stop, slowed only by friction (which you can assume is the same for both merry-go-rounds), which will take longer to stop?

i think the one with the people will take longer to stop because they have the same moment of inertia but the mass of the people one is larger.
 
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  • #2
I'd agree with you. If the force of friction is the same, and the speed is the same, the heavier merry-go-round will have more angular momentum. Therefore it will take more force to stop it.
 

FAQ: Simple rotational motion problem

What is simple rotational motion?

Simple rotational motion is a type of motion where an object moves in a circular path around a fixed point, also known as the axis of rotation. This type of motion can be observed in objects such as wheels, gears, and planets in orbit.

How is rotational motion different from linear motion?

Rotational motion involves movement around an axis, while linear motion involves movement in a straight line. In rotational motion, the distance from the axis of rotation is important, whereas in linear motion, the direction of movement is more significant.

What are the units of measurement for rotational motion?

The units of measurement for rotational motion depend on the specific quantity being measured. For angular displacement, the unit is radians (rad) or degrees (°). For angular velocity, the unit is radians per second (rad/s) or revolutions per minute (rpm). And for angular acceleration, the unit is radians per second squared (rad/s^2) or revolutions per minute squared (rpm/s^2).

How is rotational motion related to torque?

Torque is a measure of the force that causes an object to rotate around an axis. In simple rotational motion, the torque is directly proportional to the angular acceleration of the object. This means that the more torque applied to an object, the faster it will rotate.

What are some real-world examples of simple rotational motion?

Simple rotational motion can be observed in many everyday objects such as bicycle wheels, ceiling fans, merry-go-rounds, and record players. It can also be seen in larger scale systems such as the rotation of the Earth around its axis and the rotation of planets around the sun.

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