Efficiency and reducing unwanted energy transfers

In this lesson we will be exploring the topic of reducing energy losses. We will consider how this affects the efficiency of a system and use this in calculations.

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, letâ€™s see what you can remember from this topic. Hereâ€™s a quick quiz!

Q1.Which of these is the correct definition of power?

1/5

Q2.Which is the correct statement about closed systems?

2/5

Q3.What is the power of a motor that transfers 450 J of energy in 9 s?

3/5

Q4.A ball dropped from a cliff has 100 J in its GPE store as it is released. What is the value of the KE store when it just reaches the ground?

4/5

Q5.How long would it take a 400 W motor to transfer 2000 J of energy?

5/5

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, letâ€™s see what you can remember from this topic. Hereâ€™s a quick quiz!

Q1.Which of these is the correct definition of power?

1/5

Q2.Which is the correct statement about closed systems?

2/5

Q3.What is the power of a motor that transfers 450 J of energy in 9 s?

3/5

Q4.A ball dropped from a cliff has 100 J in its GPE store as it is released. What is the value of the KE store when it just reaches the ground?

4/5

Q5.How long would it take a 400 W motor to transfer 2000 J of energy?

5/5

Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the â€˜Resume Videoâ€™ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click â€˜Nextâ€™ below.

Quiz:

Efficiency and reducing unwanted transfers

This quiz will test your understanding of efficiency and unwanted transfers. Additionally it will test your understanding of earlier lessons within this topic.

Q1.Which energy store is increased when an object is heated?

1/6

Q2.What is the power of a motor that transfers 550 J of energy in 11s?

2/6

Q3.Which of these is a correct equation for percentage efficiency?

3/6

Q4.If a 0.75 efficient motor produces 150 W of useful power, what was the input power?

4/6

Q5.Which of these are ways in which a motor lifting a crate could transfer energy less usefully? (select 4)

Select four (4) boxes

5/6

Q6.Which material will have the lowest thermal conductivity?

6/6

Quiz:

Efficiency and reducing unwanted transfers

This quiz will test your understanding of efficiency and unwanted transfers. Additionally it will test your understanding of earlier lessons within this topic.

Q1.Which energy store is increased when an object is heated?

1/6

Q2.What is the power of a motor that transfers 550 J of energy in 11s?

2/6

Q3.Which of these is a correct equation for percentage efficiency?

3/6

Q4.If a 0.75 efficient motor produces 150 W of useful power, what was the input power?

4/6

Q5.Which of these are ways in which a motor lifting a crate could transfer energy less usefully? (select 4)

Select four (4) boxes

5/6

Q6.Which material will have the lowest thermal conductivity?

6/6

Lesson summary: Efficiency and reducing unwanted energy transfers

Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Walk

On the spot:
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