Understanding Power Calculations

What is the formula for calculating power?

If a machine does 300 joules of work in 15 seconds, what is its power output?

• 15 watts

• 20 watts

• 25 watts

• 30 watts

A light bulb uses 90 joules of energy in 3 seconds. Calculate the power of the light bulb.

• 20 watts

• 25 watts

• 30 watts

• 35 watts

Which of the following units is used to measure power?

• Joule

• Watt

• Newton

• Pascal

If a device has a power rating of 100 watts and operates for 4 seconds, how much work does it do?

• 200 joules

• 300 joules

• 400 joules

• 500 joules

Tags

NGSS.HS-PS3-3

A car engine produces 5000 joules of work in 25 seconds. What is the power output of the engine?

• 150 watts

• 175 watts

• 200 watts

• 250 watts

Which of the following is an example of a power calculation?

• Calculating the speed of a car

• Determining the energy used by a light bulb in a given time

• Measuring the distance traveled by a runner

• Finding the mass of an object

A machine performs 4000 Joules of work at a power of 500 Watts. How much time does it take to complete the work?

• 5 s

• 10 s

• 45 s

• 8 s