Force in a dynamics of rotation problem?

In summary, a bucket of water with a mass of 15.0 kg is suspended by a rope wrapped around a windlass, a solid cylinder with a diameter of 0.290 m and a mass of 12.4 kg. The bucket falls 11.0 m to the water and the weight of the rope is ignored. The question asks for the force exerted on the cylinder by the axle while the bucket is falling. The answer is the sum of the cylinder's weight and the tension of the rope, which is 12.4 x 9.80 + 43.0 = 166.92 N.
  • #1
erik-the-red
89
1
Question

A bucket of water of mass 15.0 kg is suspended by a rope wrapped around a windlass, that is a solid cylinder with diameter 0.290 m with mass 12.4 kg. The cylinder pivots on a frictionless axle through its center. The bucket is released from rest at the top of a well and falls a distance 11.0 m to the water. You can ignore the weight of the rope.

The fourth and final part of the question is "While the bucket is falling, what is the force exerted on the cylinder by the axle?"

Quite frankly, I don't really understand this question. When I drew the free body diagram, I'm inclined to say the answer is (12.4)(9.80).

Is this asking for the normal force?
 
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  • #2
Never mind, I got it.

I forgot that it's just (12.4)(9.80) + T, where T is 43.0 and was asked for in the first part of the question.
 
  • #3
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  • #4
I had trouble with the question intially also, because of the wording, but it makes sense: there are two forces that act on the cylinder while the bucket is falling, its own weight, and the Tension of the bucket.

By adding these, you get the total force that's acting on the cylinder.

-L.
 

What is the definition of force in a dynamics of rotation problem?

Force in a dynamics of rotation problem is the physical quantity that causes an object to rotate around an axis. It is a vector quantity, meaning it has both magnitude and direction. In rotational dynamics, force is represented using the symbol "F".

What are the different types of forces in rotational dynamics?

There are three main types of forces in rotational dynamics: torque, centripetal force, and centrifugal force. Torque is the force that causes an object to rotate, centripetal force is the force that keeps an object moving in a circular path, and centrifugal force is the perceived outward force on an object in circular motion.

How is force related to angular acceleration in rotational dynamics?

According to Newton's second law of motion, force is directly proportional to the angular acceleration of an object. This means that the greater the force applied, the greater the angular acceleration, and vice versa.

How does the distance from the axis of rotation affect force in rotational dynamics?

According to the law of moments, force is inversely proportional to the distance from the axis of rotation. This means that the farther an object is from the axis of rotation, the less force is required to produce the same amount of torque.

What are some real-life examples of rotational dynamics and force?

Examples of rotational dynamics and force in everyday life include the rotation of tires on a car, the spinning of a top, and the rotation of a merry-go-round. In each of these examples, force is applied to cause the object to rotate around an axis.

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