20. A solid disk of mass 2 kg and radius 0.5 m is rotating with an initial angular velocity of a, 4 rad/s. A bar comes in contact with it, causes friction, slows it down and eventually stops it in 5 seconds. a) b) c) What is the angular acceleration of the disc? What is the torque that will produce this angular acceleration? What is the frictional force applied by the bar?

20. A solid disk of mass 2 kg and radius 0.5 m is rotating with an initial angular velocity of a, 4 rad/s. A bar comes in contact with it, causes friction, slows it down and eventually stops it in 5 seconds. a) b) c) What is the angular acceleration of the disc? What is the torque that will produce this angular acceleration? What is the frictional force applied by the bar?

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter10: Rotational Motion

Section: Chapter Questions

Problem 4P

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Similar questions

An automobile engine can produce 200 N m of torque. Calculate the angular acceleration produced if 95.0% of this torque is applied to the drive shaft, axle, and rear wheels of a car, given the following information. The car is suspended so that the wheels can turn freely. Each wheel acts like a 15.0 kg disk that has a 0.180 m radius. The walls of each tire act like a 2.00-kg annular ring that has inside radius of 0.180 m and outside radius of 0.320 m. The tread of each tire acts like a 10.0-kg hoop of radius 0.330 m. The 14.0-kg axle acts like a rod that has a 2.00-cm radius. The 30.0-kg drive shaft acts like a rod that has a 3.20-cm radius.
A bus contains a 1500 kg flywheel (a disk that has a 0.600 m radius) and has a total mass of 10,000 kg. (a) Calculate the angular velocity the flywheel must have to contain enough energy to take the bus from rest to a speed of 20.0 m/s, assuming 90.0% of the rotational kinetic energy can be transformed into translational energy. (b) How high a hill can the bus climb with this stored energy and still have a speed of 3.00 m/s at the top of the hill? Explicitly show how you follow the steps in the Problem-Solving Strategy for Rotational Energy.
A bar on a hinge starts from rest and rotates with an angular acceleration = 10 + 6t, where is in rad/s2 and t is in seconds. Determine the angle in radians through which the bar turns in the first 4.00 s.
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