Speed of a point on the rim?

In summary, the speed of a point on the rim refers to the linear velocity of a point on the outside edge of a rotating object. It is calculated by multiplying the angular velocity of the object by the distance from the center of rotation to the point on the rim, and the unit of measurement is meters per second (m/s) in the SI system or feet per second (ft/s) in the imperial system. The speed of a point on the rim is directly related to the speed of the whole object, but will always be greater due to the larger distance from the center of rotation. Factors that can affect the speed of a point on the rim include the angular velocity, radius, external forces, and the composition and surface of the object
  • #1
05holtel
52
0

Homework Statement



A thin, 100.0 g disk with a diameter of 8.00 cm rotates about an axis through its center with 0.150 J of kinetic energy.

What is the speed of a point on the rim?


The Attempt at a Solution



1/2mv^2 = 0.15
v = 1.73m/s

I know
Vt = angular velocity x r

I am not sure how to solve foe the angular velocity
 
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  • #2
1/2 mv^2 = kinetic energy, correct. However, here you're dealing with rotational KE. You need a different formula. Does that help?
 
  • #3
in this case

I would respond by saying that the speed of a point on the rim can be calculated using the formula v=ωr, where v is the linear speed, ω is the angular velocity, and r is the radius. In this case, the kinetic energy of the rotating disk can be used to calculate the angular velocity, since the formula for kinetic energy of a rotating object is KE = 1/2Iω^2, where I is the moment of inertia. By rearranging the formula and plugging in the given values, we can solve for ω, which can then be used in the formula v=ωr to calculate the linear speed at the rim of the disk.
 

1. What is the definition of the "speed of a point on the rim"?

The speed of a point on the rim refers to the linear velocity of a point on the outside edge of a rotating object, such as a wheel or a disc.

2. How is the speed of a point on the rim calculated?

The speed of a point on the rim can be calculated by multiplying the angular velocity of the object by the distance from the center of rotation to the point on the rim. This is represented by the equation v = ωr, where v is the linear velocity, ω is the angular velocity, and r is the distance from the center to the point on the rim.

3. What is the unit of measurement for the speed of a point on the rim?

The unit of measurement for the speed of a point on the rim is meters per second (m/s) in the SI system, or feet per second (ft/s) in the imperial system.

4. How does the speed of a point on the rim relate to the speed of the whole object?

The speed of a point on the rim is directly related to the speed of the whole object. As the object rotates faster, the speed of the point on the rim also increases. However, the linear velocity of the point on the rim will always be greater than the linear velocity of the object as a whole, due to the larger distance from the center of rotation.

5. What factors can affect the speed of a point on the rim?

The speed of a point on the rim can be affected by the angular velocity of the object, the radius of the object, and any external forces acting on the object. Additionally, the composition and surface of the object can also play a role in determining the speed of a point on the rim.

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