The Student Room Group

OCR (non mei) M2 Wednesday 18th May 2016

Scroll to see replies

Ayy guys I got a question about work-energy and power:

If a car drives along a rough horizontal road and its velocity increases over time with a constant resistive force, would the change in mechanical energy be the total energy produced by the engine (power multiplied by time) MINUS the work done to over come the resistive force?

Here is the question I am referring to (part iii)):

June 2005 work-energy.png

Oh and BTW OCR MEI master race.
Reply 21
Original post by Wunderbarr
Ayy guys I got a question about work-energy and power:

If a car drives along a rough horizontal road and its velocity increases over time with a constant resistive force, would the change in mechanical energy be the total energy produced by the engine (power multiplied by time) MINUS the work done to over come the resistive force?

Here is the question I am referring to (part iii)):

June 2005 work-energy.png

Oh and BTW OCR MEI master race.

Yes, because the work done by the driving force of the car (power x time), needs to over come the work done against resistance and also account for the increase in Kinetic energy.
The nerves are kicking in now, final weekend before the exam!

I remember absolutely hating M1 last year and it worked out alright, let's hope for a repeat this year :tongue:
Original post by rich1334
The nerves are kicking in now, final weekend before the exam!

I remember absolutely hating M1 last year and it worked out alright, let's hope for a repeat this year :tongue:


Same here. On the reverse, I thought D1 was gonna be easy and not even worth spending too much time revising and then that was my lowest UMS (maybe because I was panicking after that awful physics G482 paper the previous day which also turned out alright).
Reply 25
Does anyone have the 2015 paper? My school hasn't given it to me and I would really like a proper practice before the exam on Wednesday. Pictures of the questions or anything, please I'm desperate! Thanks!
Original post by salcici
Does anyone have the 2015 paper? My school hasn't given it to me and I would really like a proper practice before the exam on Wednesday. Pictures of the questions or anything, please I'm desperate! Thanks!

I have it, will post pictures in a few minutes.
Reply 27
Original post by Vanilla Poison
I have it, will post pictures in a few minutes.


Thank you so much x
Original post by salcici
Thank you so much x

Attachment not found
Attachment not found
Reply 29
You're a life saver! Good luck for your exam hope you do really well!
Original post by salcici
You're a life saver! Good luck for your exam hope you do really well!

No worries, good luck to you too! :smile:
Reporting in. I feel like I've got much better at M2 in the past few days/weeks so I'm hoping this trend can continue through to Wednesday morning! Would love to get 95+ on this.
Hello guys, need some help. I dont quite understand how to the second part of question one of June2015. I am alao struggling to do question 5 part one in findong h. I dont know wjy im struggling with these, as i can do most other hard questions!
Original post by Sonnyjimisgod
Hello guys, need some help. I dont quite understand how to the second part of question one of June2015. I am alao struggling to do question 5 part one in findong h. I dont know wjy im struggling with these, as i can do most other hard questions!

I guess you know the work energy formula.
Initial KE + Word done by car = Final KE + Work done by friction
Work done by the car = 600 × 14.2 (rearrange power = work done/time)
Work done by friction = 60x (x is distance travelled)
Just solve for x.

For 5 I worked out the speed the sphere hits the ground with (approach speed) using SUVAT. The speed it leaves the ground with is 0.7 × approach speed. Then you can say its final velocity is zero, use suvat to find its max height (h).

Sorry if its not clear, wish I had time to learn latex
Original post by Vanilla Poison
I guess you know the work energy formula.
Initial KE + Word done by car = Final KE + Work done by friction
Work done by the car = 600 × 14.2 (rearrange power = work done/time)
Work done by friction = 60x (x is distance travelled)
Just solve for x.

For 5 I worked out the speed the sphere hits the ground with (approach speed) using SUVAT. The speed it leaves the ground with is 0.7 × approach speed. Then you can say its final velocity is zero, use suvat to find its max height (h).

Sorry if its not clear, wish I had time to learn latex


Thanks man!

I'm self teaching and for some of the questions I have some difficulty. Hopefully will get 60+/72.

Also you wish to learn about latex?
Original post by Sonnyjimisgod
Thanks man!

I'm self teaching and for some of the questions I have some difficulty. Hopefully will get 60+/72.

Also you wish to learn about latex?

http://www.thestudentroom.co.uk/wiki/LaTeX
It looks really cool
Reply 36
Force diagrams for EVERYTHING
Original post by Vanilla Poison


Haha I thought you were talking about a different kind of latex....
Original post by Sonnyjimisgod
Haha I thought you were talking about a different kind of latex....


( ͡° ͜ʖ ͡°)
(edited 7 years ago)
Does anyone know how to do part iii) a) and b) ...image.jpg

Quick Reply