A pulley has an initial angular speed of 12.5 rad/s and a constant angular accel

Question

A pulley has an initial angular speed of 12.5 rad/s and a constant angular acceleration of 3.41 rad/s^2. Through what angle does the pulley turn in 5.26 s? A) 22.6 rad B) 42.6 rad C) 113 rad D) 19.3 rad E) 160 rad 9) A person pushes on a doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from axis of the hinges of the door. The door begins to route with an angular acceleration of 2.00 rad/s^2. What is the moment of inertia of the door about the hinges? A) 6.40 kgmiddotm^2 B) 1.00 kgmiddotm^2 C) 8.00 kgmiddotm^2 D) 2.00 kgmiddotm^2 E) 12.5 kgmiddotm^2 10) In an effort to loosen the bolt on the wheel of a car, a man with a maw of 70 kg steps on the end of a 50-cm tire iron which is extending horizontally from the bolt. How much torque is he applying to the bolt? A) 14 N m B) 70 N m C) 35 N m D) 340 N m E) 140 N m 11) A board is 20.0 cm Hide, 5.00 cm thick, and 3.00 m long has a mass of 12.0 kg. The board is floating partially submerged in water. What minimum mass would need to be set on the board to submerge the board? Note that the board is submerged, but the mass resting on top of the board is not. Q_water = 1000 kg/m^3 A) 12.0 kg B) 18.0 kg C) 48.0 kg D) 30.0 kg E) 42.0 kg

Explanation / Answer

7. Area. A = 0.13 x 0.28 = 0.0364 m^2

F = mg = 57 x 9.8 N

P = F/ A = (57 x 9.8) / (0.0364) = 1.5 x 10^4 Pa

Ans(B)

8. Using , theta = wi*t + alpha*t^2 /2

theta = (12.5 x 5.26) + (3.41 x 5.26^2 / 2) = 112.9 rad

Ans(C)

9. torque = I x alpha

and torque = r x F

0.8 x 5 = I x 2

I = 2 kg m^2

Ans(D)

10. torque = r x F = 0.50 x (70 x 9.8) = 343 N m

Ans ( D)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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