Torque and Acceleration question

In summary, the problem involves a solid wheel with an initial angular velocity of 5 rad/s and a mass of 2 kg and radius of 1.5 m. After 8 rotations, the wheel comes to a stop. The angular acceleration is -24.9 rad/s^2 and the tangential acceleration at the rim is -37.4 m/s^2. The net torque is -56 Nm and the energy required to bring the wheel to a stop is 8*2pi*(-56.0Nm).
  • #1
veronicak5678
144
0

Homework Statement


A solid wheel (I = 1/2 MR^2) initially rotating at 5 rad/s comes to a stop after 8 rotations.
a) Angular acceleration?
b) Tangential accelration at the rim?
c) If the mass is 2 kg and the radius is 1.5 m, find the net torque.
d) Using values form c, how much energy was required to bring the wheel to a stop?

Homework Equations





The Attempt at a Solution


a) -24.9 rad/s^2

b) -37.4 m/s^2

c) -56 Nm

d) I am not sure how to find the energy used.
 
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  • #2
part(a) is incorrect and that error propagates through to (b) and (c)...perhaps you should show me how you got part (a)...
 
  • #3
For part a I used (w for omega for tangential velocity, a for alpha for angular acceleration )

w final ^2 - w initial^2 = 2a delta angle

(0 - (50 rad /s)^2 ) / (2 (50.3rad))

= -24.9 rad /s^2
 
  • #4
Your original post said the w_initial=5rad/s not 50...if it is 50 then your original answer is correct.

As for the energy required to stop the wheel; it should be the same as the 'work done by the torque' over an angular distance of 8*2pi...does that help?
 
  • #5
Sorry for the typo!

So the energy used will be 8* 2pi (-56.0Nm) ?
 

1. What is torque and how does it relate to acceleration?

Torque is a measure of the force that causes an object to rotate. It is the product of a force applied to an object and the distance from the axis of rotation. Torque is related to acceleration through the equation T = Iα, where T is torque, I is the moment of inertia, and α is the angular acceleration.

2. How does the direction of the applied force affect torque and acceleration?

The direction of the applied force affects torque and acceleration as it determines the direction of rotation. If the force is applied at a tangent to the rotation, it will produce a maximum torque and acceleration. If the force is applied perpendicular to the rotation, it will produce no torque and zero acceleration.

3. What is the difference between linear and angular acceleration?

Linear acceleration is the change in velocity of an object in a straight line, while angular acceleration is the change in angular velocity of an object in a circular motion. Linear acceleration is measured in m/s^2, while angular acceleration is measured in radians/s^2.

4. How does the moment of inertia affect torque and acceleration?

The moment of inertia is a measure of an object's resistance to changes in its rotation. Objects with a larger moment of inertia require more torque to produce the same angular acceleration compared to objects with a smaller moment of inertia. Therefore, the moment of inertia affects both torque and acceleration.

5. What are the applications of torque and acceleration in real life?

Torque and acceleration have various applications in everyday life, such as in the design and operation of machines, vehicles, and sports equipment. They are also important in understanding the movement of celestial bodies and the behavior of fluids. Additionally, torque and acceleration are crucial in the study of biomechanics and human movement.

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