Circular Motion of bicycle wheel

In summary, a bicycle wheel with a radius of 0.5 m completes one full turn in 1.6 seconds. Two identical rocks are stuck on the wheel at radii of 0.4 m and 0.2 m. The question asks for the ratio of the force on the outer rock to that of the inner rock. Relevant formulas include F=ma, F=mw^2r, and F=(mv^2)/r. To find the angular speed, w, we can use w=2*pi*f. However, to find the force using either F=(mv^2)/r or F=mw^2r, we would need the mass of the rocks. The question requires us to find F
  • #1
Asher242

Homework Statement


A bicycle wheel has a radius of 0.5 m. When it spins, it completes one full turn in 1.6 s. Two identical rocks are stuck on the wheel at a radius of 0.4 m and 0.2 m. What is the ratio of the force on the outer rock to that of the inner rock?

Homework Equations


F=ma
F=mw^2r
F= (mv^2)/r
These are the only formula's I believe could be relevant

The Attempt at a Solution


I've looked at both f=(mv^2)/r and f=mw^2r but I just can't get it. I don't understand how I'm supposed to find the force with on the time and the radius. This led me to believe that I don't have to necessarily solve it but after that I'm lost
 
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  • #2
Asher242 said:

Homework Statement


A bicycle wheel has a radius of 0.5 m. When it spins, it completes one full turn in 1.6 s. Two identical rocks are stuck on the wheel at a radius of 0.4 m and 0.2 m. What is the ratio of the force on the outer rock to that of the inner rock?

Homework Equations


F=ma
F=mw^2r
F= (mv^2)/r
These are the only formula's I believe could be relevant

The Attempt at a Solution


I've looked at both f=(mv^2)/r and f=mw^2r but I just can't get it. I don't understand how I'm supposed to find the force with on the time and the radius. This led me to believe that I don't have to necessarily solve it but after that I'm lost
You need the angular speed, w. The wheel completes a full turn in 1.6 s. What angle is a full turn? What is the angular speed then?
 
  • #3
Thank you so much for helping me :D

So going off of what you said I found the angular velocity to be 3.9ms (using w=2*pi*f) and from that I can also find the velocity of both of the rocks, however to find the force using either F=(mv^2)/r or F=mw^2r I would need the mass as there would be two unknown variables. Do I make up my own mass? (I've seen my teacher do it before) but, if everyone constructs their own mass it would be impossible to get the same answer right? Or, am I using the wrong formulas...
 
  • #4
Asher242 said:
I found the angular velocity to be 3.9ms (using w=2*pi*f)
Your units are incorrect here.

But more importantly, pay attention to the bit of the question that requires you to find the ratio of two forces.

Write down the force equation for each rock separately, without plugging in any numbers. Just the symbols.
The question asks you to find ##F_1/F_2##. See if any variables cancel out.
 

1. What is circular motion of a bicycle wheel?

Circular motion of a bicycle wheel refers to the continuous rotation of the wheel around its center point. This motion is caused by the force applied by the rider's pedaling, and it produces the movement of the bicycle.

2. What factors affect the circular motion of a bicycle wheel?

The main factors that affect the circular motion of a bicycle wheel include the force applied by the rider, the mass of the wheel, the diameter of the wheel, and any external forces such as friction from the ground or air resistance.

3. How does centripetal force play a role in circular motion of a bicycle wheel?

Centripetal force is the force that acts towards the center of a circular motion, keeping the object moving in a circular path. In the case of a bicycle wheel, this force is provided by the tension in the spokes and the friction between the tires and the ground.

4. How does angular momentum relate to the circular motion of a bicycle wheel?

Angular momentum is the measure of an object's rotational motion. In the case of a bicycle wheel, the angular momentum is created by the force applied by the rider's pedaling, and it is maintained by the conservation of angular momentum as the wheel continues to rotate.

5. How does the circular motion of a bicycle wheel affect its stability?

The circular motion of a bicycle wheel is essential for maintaining stability while riding. The spinning motion of the wheel creates a gyroscopic effect, which helps to keep the bicycle upright and balanced. This effect is what allows riders to steer and maintain their balance while moving.

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