Physics 163

Unit 5: Work, Energy and Power

Problem Set A

Problem 7:

Jack runs up the stairs, elevating his 71.8 kg body a vertical distance of 2.39 meters in a time of 1.59 seconds. Determine the power (in Watts) done by the stairs on Jack's body.

• Read the problem carefully and diagram the physical situation
• Identify known and unknown information in an organized manner
• Take the time to plot out a strategy prior to beginning the solution
• Identify an appropriate formula to use
• Perform step-by-step algebraic manipulations

Work, energy and power concepts can be reviewed on the Set A Overview page.

Further information about the concept of and equation for power is available online at The Physics Classroom.

Further information about the mass-weight relationship is available online at The Physics Classroom.

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