Questions from Modern Physics

Q: A bicycle racer is going downhill at 11.0 m/

A bicycle racer is going downhill at 11.0 m/s when, to his horror, one of his 2.25-kg wheels comes off as he is 75.0 m above the foot of the hill. We can model the wheel as a thin-walled cylinder 85.0...

Q: A playground merry-go-round has radius 2.40

A playground merry-go-round has radius 2.40 m and moment of inertia 2100 kg#m2 about a vertical axle through its center, and it turns with negligible friction. (a) A child applies an 18.0-N force tang...

Q: An engine delivers 175 h p to an aircraft propeller at 2400

An engine delivers 175 h p to an aircraft propeller at 2400 rev/min. (a) How much torque does the aircraft engine provide? (b) How much work does the engine do in one revolution of the propeller?

Q: A 2.80-kg grinding wheel is in the form

A 2.80-kg grinding wheel is in the form of a solid cylinder of radius 0.100 m. (a) What constant torque will bring it from rest to an angular speed of 1200 rev/min in 2.5 s? (b) Through what angle has...

Q: An electric motor consumes 9.00 kJ of electrical energy in

An electric motor consumes 9.00 kJ of electrical energy in 1.00 min. If one-third of this energy goes into heat and other forms of internal energy of the motor, with the rest going to the motor output...

Q: (a) Compute the torque developed by an industrial motor whose

(a) Compute the torque developed by an industrial motor whose output is 150 kW at an angular speed of 4000 rev/min. (b) A drum with negligible mass, 0.400 m in diameter, is attached to the motor shaft...

Q: An airplane propeller is 2.08 m in length (from

An airplane propeller is 2.08 m in length (from tip to tip) and has a mass of 117 kg. When the airplane’s engine is first started, it applies a constant torque of 1950 N.m to the propeller, which star...

Q: A 2.00-kg rock has a horizontal velocity of

A 2.00-kg rock has a horizontal velocity of magnitude 12.0 m/s when it is at point P in Fig. E10.35. (a) At this instant, what are the magnitude and direction of its angular momentum relative to point...

Q: A woman with mass 50 kg is standing on the rim of

A woman with mass 50 kg is standing on the rim of a large disk that is rotating at 0.80 rev/s about an axis through its center. The disk has mass 110 kg and radius 4.0 m. Calculate the magnitude of th...

Q: If two spinning objects have the same angular momentum, do they

If two spinning objects have the same angular momentum, do they necessarily have the same rotational kinetic energy? If they have the same rotational kinetic energy, do they necessarily have the same...