Unlock access to content

Select one option:

Free of charge

Unlock the chapter "Energy, Work and Power"

Unlock access to the solution of problems in this chapter.
Free of charge Price: 3.00 £

Continue »

Subscribe to OpenProf If you do not get a better grade, you get your money back!

Unlock access to all problems solutions.
Available from 8.25 £ / month.

Continue »

Unlock the chapter

Select one option:

Free of charge Send SMS code Confirming your phone number unlocks access to detailed solution steps for "Energy, Work and Power" for 3 months. 0 £

Buy chapter access Purchasing gives you access to detailed solution steps for the problems in "Energy, Work and Power" chapter for 3 months. 3.00 £

« Back

Unlock the chapter

“Energy, Work and Power”

Free of charge

Send SMS code

Please confirm your age:

I am 15 years old or older »

No, I'm not 15 years old or older »

You can only unlock the chapter using a special code that we will send you via SMS. Receiving an SMS is free of charge and with no obligations.

My phone number:

Get an SMS code

In compliance with the law, persons under the age of 15 can enter their phone number only in the presence of a parent or guardian.

4-character SMS code:

Check the received SMS code

The page will be refreshed automatically in a few seconds.

Enter your phone number

Enter the SMS authorisation code

« Back

Social networks

OpenProf

No password sign in

User login

Remember me

Not registered yet? | Forgot your password?

« Select another login method

No password sign in

[For registered users only]

We are sending a message to your e-mail...

To the following e-mail address:

we sent you a message with a link. By clicking on the link, you will automatically log in to your profile.

Attention! The connection is valid for 15 minutes. The message is sent only if the user with the given username (e-mail address) exists in the database.

Please try again?

The message hasn't arrived yet?

Please check:

spelling of the e-mail address;
different tabs, such as "Promotions" in Gmail;
spam (and tag our mail as trustworthy).

Not registered yet?

« Select another login method

Export chapter

Include theory

Include problems

Include answers

[why disabled?]

Exporting final solutions in PDF format is available to subscribers.

You have reached your daily / monthly download limit.

Export chapter

Document creation in progress. The creation process can take several seconds, please wait.

An error occurred creating the document.

Please try again

Energy, Work and Power

Energy, Work and Power problem 8

« previous problem | next problem »

How long does a 420 W machine have to work to do 630 kJ of work?

The detailed solution steps are locked. Click on the blue button to unlock them.

Unlock the detailed solution steps »

Show solution

The machine must work for 25 minutes.

To view the solution, you need to log in.

You must confirm your username (email address) to view the solution.

Confirm username »

You must confirm your username (email address) to view the solution.

Confirm username »

Discussion forum

material editor: Gabriel Amakhabi