A torsion pendulum is made from a disk of mass m = 7 kg and radius R = 0.66 m. A

Question

A torsion pendulum is made from a disk of mass m = 7 kg and radius R = 0.66 m. A force of F = 40.8 N exerted on the edge of the disk rotates the disk 1/4 of a revolution from equilibrium.

1)What is the torsion constant of this pendulum? ------>>> answer is ( 17.14)

2) What is the minimum torque needed to rotate the pendulum a full revolution from equilibrium? --->> answer is (107.712)

I NEED HELP WITH NEXT QUESTIONS

3) What is the angular frequency of oscillation of this torsion pendulum? IN RAD/S

4) Which of the following would change the period of oscillation of this torsion pendulum? YOU CAN CHOOSE MORE THAN ONE

A- increasing the mass

B- decreasing the initial angular displacement

C- replacing the disk with a sphere of equal mass and radius

D- hanging the pendulum in an elevator accelerating downward

Explanation / Answer

1)the torsion constant of this pendulum
= 40.8 * 0.66 / (0.5* pi )
= 17.14 Nm/ rad ---answer

2)the minimum torque needed to rotate the pendulum a full revolution from equilibrium
= 17.14 * 2 pi
= 107.69 Nm ---answer

3) moment of inertia
= 7 * 0.66^2 / 4
= 0.7623
Torque = MoI * angular acc
107.69 = 0.7623 * a
a= 141.269 rad /s2

s = ut + 0.5 at^2
2 pi = 0 + 0.5 * 107.69 * t^2
t = 0.34 s = period

angular frequency of oscillation of this torsion pendulum
= 1 / t = 2.94 Hz ---answer

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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