Edexcel Physics AS Physics on the Go Unit 1 RETAKE

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It goes both vertically and horizontally greater than the smaller angle. I actually worked it out with suvats in the exam quickly

But how?

It's with the same velocity. So the forward component will be less?

Reply 61

jack.lp.thompson

Original post by KINGYusuf

But how?

It's with the same velocity. So the forward component will be less?

That's what I thought. Surely, it will be a short distance. But apparently it's because it's closer to 45 degrees which is the furthest a ball can travel?? Idk 😕

Reply 62

jack.lp.thompson

Do you all think the grade boundaries will be really high because there no y12 doing it but all resits??

Reply 63

jtebbbs

For the work done on the pogo stick, it's equal to the area under the graph between 3cm and 9cm, which comes out as 130.5J. For the max velocity, elastic potential is converterd to kinetic energy and GPE (work is done moving the kid upwards) so kinetic = elastic potetnial - mgΔh, giving a max velocity of about 2.5m/s.

Reply 64

KINGYusuf

Original post by jtebbbs

I wrote and GPE aswell, but then isn't there no GPE as the kid is still on the ground i.e. the pogo stick is still touching the ground lol

Reply 65

jtebbbs

Original post by Ezio.

It goes both vertically and horizontally greater than the smaller angle. I actually worked it out with suvats in the exam quickly

It goes further vertically and not as far horizontally. The magnitude of the velocity stays the same so if one component increases, the other must decrease

(edited 7 years ago)

Reply 66

KINGYusuf

Original post by jtebbbs

It goes further vertically and not as far horizontally. The magnitude of the velocity stays the same so if one component increases, the other must decreast

Yes this is what I got!!!

Reply 67

jtebbbs

Original post by KINGYusuf

I wrote and GPE aswell, but then isn't there no GPE as the kid is still on the ground i.e. the pogo stick is still touching the ground lol

If the pogo stick was a lift and the kid stood on it and went up, he'd still gain GPE without leaving the ground, the physics is the same

Plus 4 marks for getting v from KE is too much anyway

Reply 68

jtebbbs

Original post by extreamedice

Ah and the MCQ question where i found to be the most confusing was the steel ball and plastic ball dropped in vacuum. after they drop the same height they will have the same velocity right? or will they have the same resultant force acting on them? I picked same velocity cause acceleration is 9.81 so yea..

Yeah force, kinetic energy and the other one (can't remember) are all dependent on mass, which is different for each ball, velocity is the only one that isn't

Reply 69

KINGYusuf

Original post by jtebbbs

If the pogo stick was a lift and the kid stood on it and went up, he'd still gain GPE without leaving the ground, the physics is the same

Plus 4 marks for getting v from KE is too much anyway

I hope you're right :biggrin:

I wrote down GPE just incase.

btw I know I defo got the graph wrong of velocity-time of terminal velocity

I did constant gradient with a horizontal line, but it was supposed to be a curve then a horizontal line wasn't it :frown:

Reply 70

jtebbbs

Original post by KINGYusuf

I hope you're right :biggrin:

Yeah I looked at that and thought constant gradient (=g) straight away, then changed it to curve then horizontal after!

Reply 71

extreamedice

Original post by jack.lp.thompson

Do you all think the grade boundaries will be really high because there no y12 doing it but all resits??

Well there are also none of those really smart people who get 78/80 and stuff.. so the grade boundaries wont be pulled up greatly neither will it be pulled down greatly.

Reply 72

KINGYusuf

The thing is the Q I got wrong about the 130J, I got 144J, the sad thing is that I knew I had to equate kinetic energy to this to find v, but I won't get the marks cos I didn't get 126J or what you were supposed to get

Reply 73

AdamThePhysicsMo

What did people put for the MCQ about the 5kg brick and the resistive forces

I put the one that was like 5 x (0.9-9.81) but i had no idea haha

Reply 74

jtebbbs

Original post by KINGYusuf

Guys what did everyone put as the 2 reasons for the errors of the cup thingy?

First one I put air resistance/drag and the fact that work is being done against drag so kinetic energy less (idk)

Second one I wasn't too sure, I didn't mention temperature again as the previous Q I mentioned temperature, so I wrote something random about parallax error and that you couldn't distribute all of the fluid through the hole as some will get stuck around the hole/not go in properly again I have no idea

I wrote about parallax and varying paint levels too, then about temperature again, I thought maybe saying hotter paint => shorter time would be worth a mark or something

Reply 75

jtebbbs

Original post by AdamThePhysicsMo

What did people put for the MCQ about the 5kg brick and the resistive forces

I put the one that was like 5 x (0.9-9.81) but i had no idea haha

Found that one really hard too, I guessed ma=mg+R, so R=ma-mg=5(0.9-9.81), but wasn't sure cause I would've thought ma=mg MINUS R but that's not an option

(edited 7 years ago)

Reply 76

TheTopStudent

Original post by jtebbbs

Found that one really hard to, I guessed ma=mg+R, so R=ma-mg=5(0.9-9.81), but wasn't sure cause I would've thought ma=mg MINUS R but that's not an option

Exactly what I thought, but not an option

Reply 77

123321123

Original post by KINGYusuf

How did i get 144j guys people got 126 or 128?

Hi I got 144J at first as well, but i knew it was wrong, so I read the question on the top again carefully, and i found that the question asked the work done by the child's weight, which does not include the work down by the initial 3 cm(extension ), so you need to menus the work done for the first 3 extension by 144J

Reply 78

anjelah

I got 126J for the pogo stick question!! It took a bit of trial and error but you use the graph and mark across from 6cm. Then work done is force*distance so the force from the graph times 0.06 gives you 126J :smile: