The math of energy

Find the work needed to lift a 40 N book 5 meters.

• (40 N)(5 m) =

  200 Joules

• (40 N)(5 m) =

  200 Watts

A person weighing 500 N climbs 3 meters in 5 seconds. How much WORK did they do?

A person weighing 500 N climbs 3 meters in 5 seconds. How much POWER did they use?

What are the units for ANY kind of energy?

• Newtons

• Watts

• Joules

• meters

What are the units for work?

• Newtons

• Watts

• Joules

• meters

What are the units for power?

• Newtons

• Watts

• Joules

• meters

In the equation PE_g=mgh, the value for g is always

• 10 m/s²

• 9 m/s²

• 4186 m/s²

• 9.8 m/s²

A rock with a mass of 2500 kg rests on the edge of a cliff that is 250 m above a canyon floor. Find the gravitational potential energy of the rock relative to the canyon floor.

• (2500 kg)(9.8 m/s²)(250 m)=6125000 Newtons

• (2500 kg)(9.8 m/s²)(250 m)=6125000 Watts

• (2500 kg)(9.8 m/s²)(250 m)=6125000 Joules

An athlete with a mass of 77 kg is running with a speed of 6.5 m/s. What is her kinetic energy?

Which of the following is measured in Joules? (Choose all that apply)

• Kinetic Energy

• Gravitational Potential Energy

• Work

• Power