Module 6—Work and Energy

Lesson 4—Work and Power

 

Get Focused

 

A photograph shows a series of chairs, all filled by skier, of a chairlift. There are also two skiers on the ground.

© Mike Flippo/shutterstock

Have you ever been on a chairlift, when it suddenly stopped halfway up the hill? Has this ever happened to you when it was cold and windy? When it’s windy and you’re dangling from a chair high above the ground, things can get very uncomfortable very quickly. The less time you spend hanging on the chairlift, enduring winter weather, the better.

 

Have you ever been skiing on your winter holidays? If so, you have likely witnessed large lineups for the lifts. During these times, people spend more time in line and less time enjoying potential-kinetic energy transfers (skiing).

 

Is there a common solution to both of these problems?

 

In considering the safety risks with people enduring bitter cold while suspended high above the ground and the frustration of skiers waiting in lineups, it became evident that a new kind of chairlift was needed—a “high-speed chair.” As the name clearly suggests, this chairlift simply goes faster than the older chairlifts, moving riders up the hill at a faster rate. The result is that individuals spend less time waiting for, and riding, the chairlift and more time skiing. Everybody wins. Or do they?

 

The ski-hill operator has to pay for electricity to operate the lift. This cost is passed on to the customers when they purchase lift tickets. If the new high-speed chair replaces an older, slower chairlift and follows the same route as the original, will it cost more or less money to operate? The answer to this depends on how much power is required to operate the lift and on its efficiency.

 

 In this lesson you will explore the following questions:

Module 6: Lesson 4 Assignment

 

Your teacher-marked Module 6: Lesson 4 Assignment requires you to submit a response to the following:

You must decide what to do with the questions that are not marked by the teacher.

 

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.

 

Watch and Listen

 

Other than speed, what is different in a faster ski lift? Watch the chairlift simulation titled The Relationship Between Power and Work.