A uniform disk with mass m = 8.78 kg and radius R = 1.42 m lies in the x-y plane

Question

A uniform disk with mass m = 8.78 kg and radius R = 1.42 m lies in the x-y plane and centered at the origin. Three forces act in the +y direction on the disk: a force 319 N at the edge of the disk on the +x-axis. a force 319 N at the edge of the disk on the y-axis, and a force 319 N acts at the edge of the disk at an angle theta = 39 degree above the -x-axis. What is the magnitude of the torque on the disk about the z axis due to F_1? What is the magnitude of the torque on the disk about the z axis due to F_2? What is the magnitude of the torque on the disk about the z axis due to F_3? What is the x-component of the net torque about the z axis on the disk? What is the y-component of the net torque about the z axis on the disk? What Is the z-component of the net torque about the z axis on the disk? What is the magnitude of the angular acceleration about the z axis of the disk? If the disk starts from rest, what is the rotational energy of the disk after the forces have been applied for t = 1.7 s?

Explanation / Answer

5) Y component of torque = 0 Nm as all forces are in xy plane.

6) Z componrnt of torque = [ -319 *1.42 +319*1.42*sin 39 degree]

                           = -167.91 Nm

7) angular acceleration = Torque/I

             = 167.91/(0.5*8.78*1.42^2)       

         = 18.96 rad/s^2

8) Energy = 0.5iw^2

     = 0.5*(0.5*8.78*1.42^2)*(18.96*1.7)^2

= 4598 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.