HELP WITH THIS PHYSICS QUESTION PLEASE!

  • 0 votes

I am stuck on this question in a Physics GCSE Multiple Choice paper:

In order to reach the ceiling, Jo climbs on a stool.

 Her mass is 60 kg and the stool is 80 cm high.

 It takes her 1.5 s to climb and then stand straight on the stool.

 Gravitational field strength is 10 N/kg.

 What is Jo’s average power for the climb?

Th answer is 320W but could someone please explain to me why?

Posted Tue 5th June, 2012 @ 19:59 by Ellie

4 Answers

  • 1 vote

The equation you need to use is P= e/t 

P= Power, watts

e= energy, joules

t= time, seconds.

We already have the time ( 1.5 s) , so we need to find the energy using the equation:

mass* distance traveled* gravitational field strength

mass= kg

distance traveled = meters

So, 60*0.8= 48, multiply this by 10 ( the gravitational field strength)

= 480

Put this back into the original equation P=e/t, 480/1.5 which equals 320 watts

I hope this is okay! I'm not very good at explaining things ;/ If you need any more help I am happy to help :) 

Answered Tue 5th June, 2012 @ 21:36 by Little Miss Chatterbox
  • 1 vote

thank you sooo much!

its Edexcel Additonal Science P2 :)

Answered Tue 5th June, 2012 @ 22:17 by Ellie
  • 0 votes

What exam are you doing? :) 

Answered Tue 5th June, 2012 @ 21:37 by Little Miss Chatterbox
  • 0 votes

You're welcome :) I did the AQA P2 exam last week! Good luck with your revision :)

Answered Wed 6th June, 2012 @ 11:37 by Little Miss Chatterbox