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Lesson: Newton’s Second Law of Motion for Rotation

Worksheet: Newton’s Second Law of Motion for Rotation • 11 Questions


A flywheel with a moment of inertia of kg.m2, that has an initial angular velocity of 52.36 rad/s is brought to rest by frictional torque in a time of 120 s. What is the average frictional torque on the flywheel?


A constant torque is applied to a rigid body whose moment of inertia is 4.0 kg⋅m2 around the axis of rotation. If the wheel starts from rest and attains an angular velocity of 20.0 rad/s in 10.0 s, what is the applied torque?


Suppose you exert a force of 180 N tangential to a 0.280-m-radius, 75.0-kg grindstone (a solid disk).

What torque is exerted?

What is the angular acceleration assuming negligible opposing friction?

What is the angular acceleration if there is an opposing frictional force of 20.0 N exerted 1.50 cm from the axis?


A block of mass 3.0 kg slides down an inclined plane at an angle of , as shown. The block is attached to one end of a massless tether. The other end of the tether is attached to a pulley at the top of the incline. The pulley has mass of 1.0 kg, a radius of 0.50 m, and can be approximated as a disk. The coefficient of kinetic friction of the block on the plane is 0.40. What is the magnitude of the acceleration of the block?


An automobile is suspended so that its wheels can turn freely. Each wheel acts like a disk of mass 15.0 kg with a 0.180-m radius. The walls of each tire act like an annular ring of mass 2.00 kg that has inside radius of 0.180 m and outside radius of 0.320 m. The tread of each tire acts like a hoop with a mass of 10.0 kg and a radius 0.330 m. The axle acts like a rod with a 14.0 kg mass that has a 2.00-cm radius. The drive shaft acts like a rod of mass 30.0 kg that has a 3.20-cm radius. The automobile’s engine can produce 200.0 N.m of torque. Calculate the magnitude of the angular acceleration produced by the engine if of this torque is applied to the drive shaft, axle, and rear wheels of a car.