Thursday, February 16, 2017

Activity 87: Rotational Kinetic Energy





Derivation of Rotational Energy Equation


net W  = (net F )Δs 

net W  = (r  net F )Δs/r 

net W  = (net τ)θ 


 net τ = Iα

 net W  = Iαθ

























Consider a person who spins a large grindstone by placing her hand on its edge and exerting a force through part of a revolution . In this example, we verify that the work done by the torque she exerts equals the change in rotational energy.

(a) How much work is done if she exerts a force of 200 N through a rotation of 1.00 rad(57.3º) ? The force is kept perpendicular to the grindstone’s 0.320-m radius at the point of application, and the effects of friction are negligible.


(b) What is the final angular velocity if the grindstone has a mass of 85.0 kg?


(c) What is the final rotational kinetic energy? (It should equal the work.)

Assignment:

Do Problems 21, 22,23,24,25, 27 & 28 on page 357 in the textbook.
 When you are done check your answers here.

Complete this worksheet

When done check your answer here.

No comments:

Post a Comment