# Physics homework

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#1
I need some help. D: I don’t know what equations to use?

A 1450kg car accelerates uniformly from rest. It reaches 24 m/s in 9.2s. Calculate the force needed to cause this acceleration. 
1
2 years ago
#2
v = u + at
F = ma
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2 years ago
#3
(Original post by polsan)
I need some help. D: I don’t know what equations to use?

A 1450kg car accelerates uniformly from rest. It reaches 24 m/s in 9.2s. Calculate the force needed to cause this acceleration. 
Use SUVAT (v = u + at) to find the acceleration, then use F = ma with the acceleration you just worked out to find the force required.
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#4
thank you all! i was probably confused as i dont think i was taught the v = u + at before this homework which is weird, but thank you again!
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2 years ago
#5
First you want to use the SUVAT equation You want to find a so you plug the values in Since the car accelerates uniformly , and you are given the other values
After finding the acceleration using SUVAT, just use to find the force required.
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2 years ago
#6
(Original post by TheEpicToaster)
Use SUVAT (v = u + at) to find the acceleration, then use F = ma with the acceleration you just worked out to find the force required.
What is SUVAT?

And shouldn't you use a = (v-u)/t

Then use F=ma to find out the force
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2 years ago
#7
I would assume you are in first year A-levels. You should take a quick look through the 4 (5 if you count the last one I mention) and try to memorise them ASAP and the derivations.

1) v = u + at
2) s = (u+v)/2 * t
3) s = ut + 1/2(at^2)
4) v^2 = u^2 + 2as
5) s = vt - 1/2(at^2)

I'd assume you know what all the symbols mean
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2 years ago
#8
(Original post by _Mia101)
What is SUVAT?

And shouldn't you use a = (v-u)/t

Then use F=ma to find out the force
SUVAT is a commonly used term for the equations of motion. When you rearrange v = u + at, you get a = (v-u)/t, but since the car starts at rest, u = 0, so a = v/t.
1
2 years ago
#9
(Original post by TheEpicToaster)
SUVAT is a commonly used term for the equations of motion. When you rearrange v = u + at, you get a = (v-u)/t, but since the car starts at rest, u = 0, so a = v/t.
Oh, okay thanks!
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#10
(Original post by Guarddyyy)
I would assume you are in first year A-levels. You should take a quick look through the 4 (5 if you count the last one I mention) and try to memorise them ASAP and the derivations.

1) v = u + at
2) s = (u+v)/2 * t
3) s = ut + 1/2(at^2)
4) v^2 = u^2 + 2as
5) s = vt - 1/2(at^2)

I'd assume you know what all the symbols mean
Surprisingly, I’m actually in year 11 lol
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2 years ago
#11
(Original post by _Mia101)
Oh, okay thanks!
You're welcome!
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2 years ago
#12
(Original post by polsan)
Surprisingly, I’m actually in year 11 lol
Start learning early 1
2 years ago
#13
(Original post by _Mia101)
What is SUVAT?

And shouldn't you use a = (v-u)/t

Then use F=ma to find out the force
s- displacement
u = initial velocity
v= final velocity
a = acceleration
t= time

There's a set of equations used when acceleration is constant ...(I started to learn in AS)
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#14
I didn’t know about SUVAT but since it’s been explained it’ll be really useful for me, so thank you! I actually struggle with physics the most out of biology and chemistry, but I feel like it’s getting easier to handle... 🤔
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2 years ago
#15
(Original post by Spannerin'moi)
s- displacement
u = initial velocity
v= final velocity
a = acceleration
t= time

There's a set of equations used when acceleration is constant ...(I started to learn in AS)
Thanks!
Would it be too early to start learning them in year 10?
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#16
(Original post by _Mia101)
Thanks!
Would it be too early to start learning them in year 10?
From a Year 11, I definitely don’t remember this stuff, but if you really want to consolidate learning I think it’s useful to remember outside of your the topic you’re doing currently. I think it’s good practice to go over equations, especially for Physics
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2 years ago
#17
If you plan to do physics, there's no harm in having a look in the future content. Getting your head around the basic principles is always the best, then you can do a range of questions.
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2 years ago
#18
(Original post by polsan)
From a Year 11, I definitely don’t remember this stuff, but if you really want to consolidate learning I think it’s useful to remember outside of your the topic you’re doing currently. I think it’s good practice to go over equations, especially for Physics
Okay, thanks!
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2 years ago
#19
(Original post by _Mia101)
Thanks!
Would it be too early to start learning them in year 10?
^^ No probs!
I'd say its always better to familiarize yourself with it ...so it gets easier in Year 12^^
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2 years ago
#20
(Original post by Spannerin'moi)
^^ No probs!
I'd say its always better to familiarize yourself with it ...so it gets easier in Year 12^^
Yeah true, but I don't know if I'll do physics at A-Level yet.
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