Questions from College Physics

Q: An engine has a 30.0% efficiency. The engine

An engine has a 30.0% efficiency. The engine raises a 5.00 kg crate from rest to a vertical height of 10.0 m, at which point the crate has a speed of 4.00 m/s. How much heat input is required for this...

Q: A motorcycle is speeding on a straight, level highway at constant

A motorcycle is speeding on a straight, level highway at constant speed. At t = 0, the motorcycle passes a police car that is initially at rest. The officer gives chase, but the motorcyclist doesn&aci...

Q: A magnesium ion Mg2+ is accelerated through a potential difference of

A magnesium ion Mg2+ is accelerated through a potential difference of 22 kV. What is the de Broglie wavelength of this ion?

Q: An electric power station generates steam at 500.0°C

An electric power station generates steam at 500.0°C and condenses it with river water at 27°C. By how much would its theoretical maximum efficiency decrease if it had to switch to cooling towers that...

Q: A 0.50 kg block of iron [c = 0

A 0.50 kg block of iron [c = 0.44 kJ/(kg·K)] at 20.0°C is in contact with a 0.50 kg block of aluminum [c = 0.900 kJ/(kg·K)] at a temperature of 20.0°C. The system is completely isolated from the rest...

Q: An oil-burning electric power plant uses steam at 773 K

An oil-burning electric power plant uses steam at 773 K to drive a turbine, after which the steam is expelled at 373 K. The engine has an efficiency of 0.40. What is the theoretical maximum efficiency...

Q: The efficiency of a muscle during weight lifting is equal to the

The efficiency of a muscle during weight lifting is equal to the work done in lifting the weight divided by the total energy output of the muscle (work done plus internal energy dissipated in the musc...

Q: An inventor proposes a heat engine to propel a ship, using

An inventor proposes a heat engine to propel a ship, using the temperature difference between the water at the surface and the water 10 m below the surface as the two reservoirs. If these temperatures...

Q: A power plant burns coal to produce pressurized steam at 535 K

A power plant burns coal to produce pressurized steam at 535 K. The steam then condenses back into water at a temperature of 323 K. (a) What is the maximum possible efficiency of this plant? (b) If...

Q: A heat engine uses the warm air at the ground as the

A heat engine uses the warm air at the ground as the hot reservoir and the cooler air at an altitude of several thousand meters as the cold reservoir. If the warm air is at 37°C and the cold air is at...