Exploring Work and Power Concepts

A 10 kg box is pushed across a floor with a constant force of 50 N over a distance of 5 meters. Calculate the work done by the force on the box.

A car engine does 150,000 J of work in 10 seconds. What is the power output of the engine?

A crane lifts a 500 kg load to a height of 20 meters in 25 seconds. Determine the power used by the crane, assuming no energy is lost.

• 392 W

• 3,920 W

• 39,200 W

• 392,000 W

A cyclist exerts a force of 200 N to pedal a bike over a distance of 100 meters. If the work done is 20,000 J, what is the angle between the force and the direction of motion?

• 0 degrees

• 30 degrees

• 45 degrees

• 60 degrees

A 60 W light bulb is used for 5 hours. Calculate the total energy consumed by the bulb in kilowatt-hours (kWh).

• 0.3 kWh

• 0.6 kWh

• 1.2 kWh

• 3.0 kWh

A motor does 500 J of work in 2 seconds. If the efficiency of the motor is 80%, what is the actual power output?

• 200 W

• 250 W

• 300 W

• 400 W

A person lifts a 10 kg object vertically upwards with a force of 120 N over a distance of 2 meters. Calculate the work done against gravity.

• 20 J

• 100 J

• 200 J

• 240 J

A wind turbine generates 2 MW of power. If it operates for 6 hours, how much energy does it produce in megajoules (MJ)?

• 12 MJ

• 72 MJ

• 7,200 MJ

• 12,000 MJ

A 1000 kg car accelerates from rest to a speed of 20 m/s in 10 seconds. Calculate the average power developed by the engine during this time.

• 10,000 W

• 20,000 W

• 30,000 W

• 40,000 W

A machine lifts a 200 kg object to a height of 10 meters in 5 seconds. If the machine operates at 75% efficiency, what is the input power required?

• 520 W

• 5200 W

• 2600 W

• 3900 W