# Equations of Motion - Constant Acceleration (M1 Mechanics Help) Watch

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Hello,

I am new to the forum. I have just started my A-Levels and am studying Biology, Chemistry, and Maths. Maths used to prove no difficulty for me in the past, but I am doing my homework for M1 now - Kinematics/Equation of Motion/Constant Acceleration, and I just need to be sent in the right direction of how to answer exam-style questions. I never liked Physics stuff but I like Maths, and I really like my Pure Maths.

So, one of the questions is:- M1 January 2009

"A train travels along a straight horizontal track with constant acceleration. Points A, B and C are on the track with B between A and C. The distance AB is 1200m and the distance BC is 2500m. As the train passes B, its speed is 26ms-1. The train takes 60s to travel from A to B."

(a) Find the speed of the train as it passes A. [3]

(b) Determine the acceleration of the train. [3]

(c) Calculate the speed of the train as it passes C, giving your answers to one decimal place. [3]

I would appreciate if you could show me how to answer, as well as providing the answer. I don't see my maths teacher until next week when the homework is due, so I would like help beforehand so I don't fall behind. I know to use the SUVAT equations but I don't know how to for this question.

I don't want to cheat my homework - only just to see how to answer. That's all. Thank you!

I am new to the forum. I have just started my A-Levels and am studying Biology, Chemistry, and Maths. Maths used to prove no difficulty for me in the past, but I am doing my homework for M1 now - Kinematics/Equation of Motion/Constant Acceleration, and I just need to be sent in the right direction of how to answer exam-style questions. I never liked Physics stuff but I like Maths, and I really like my Pure Maths.

So, one of the questions is:- M1 January 2009

"A train travels along a straight horizontal track with constant acceleration. Points A, B and C are on the track with B between A and C. The distance AB is 1200m and the distance BC is 2500m. As the train passes B, its speed is 26ms-1. The train takes 60s to travel from A to B."

(a) Find the speed of the train as it passes A. [3]

(b) Determine the acceleration of the train. [3]

(c) Calculate the speed of the train as it passes C, giving your answers to one decimal place. [3]

I would appreciate if you could show me how to answer, as well as providing the answer. I don't see my maths teacher until next week when the homework is due, so I would like help beforehand so I don't fall behind. I know to use the SUVAT equations but I don't know how to for this question.

I don't want to cheat my homework - only just to see how to answer. That's all. Thank you!

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#2

(Original post by

Hello,

I am new to the forum. I have just started my A-Levels and am studying Biology, Chemistry, and Maths. Maths used to prove no difficulty for me in the past, but I am doing my homework for M1 now - Kinematics/Equation of Motion/Constant Acceleration, and I just need to be sent in the right direction of how to answer exam-style questions. I never liked Physics stuff but I like Maths, and I really like my Pure Maths.

So, one of the questions is:- M1 January 2009

"A train travels along a straight horizontal track with constant acceleration. Points A, B and C are on the track with B between A and C. The distance AB is 1200m and the distance BC is 2500m. As the train passes B, its speed is 26ms-1. The train takes 60s to travel from A to B."

(a) Find the speed of the train as it passes A. [3]

(b) Determine the acceleration of the train. [3]

(c) Calculate the speed of the train as it passes C, giving your answers to one decimal place. [3]

I would appreciate if you could show me how to answer, as well as providing the answer. I don't see my maths teacher until next week when the homework is due, so I would like help beforehand so I don't fall behind. I know to use the SUVAT equations but I don't know how to for this question.

I don't want to cheat my homework - only just to see how to answer. That's all. Thank you!

**ryanjj14**)Hello,

I am new to the forum. I have just started my A-Levels and am studying Biology, Chemistry, and Maths. Maths used to prove no difficulty for me in the past, but I am doing my homework for M1 now - Kinematics/Equation of Motion/Constant Acceleration, and I just need to be sent in the right direction of how to answer exam-style questions. I never liked Physics stuff but I like Maths, and I really like my Pure Maths.

So, one of the questions is:- M1 January 2009

"A train travels along a straight horizontal track with constant acceleration. Points A, B and C are on the track with B between A and C. The distance AB is 1200m and the distance BC is 2500m. As the train passes B, its speed is 26ms-1. The train takes 60s to travel from A to B."

(a) Find the speed of the train as it passes A. [3]

(b) Determine the acceleration of the train. [3]

(c) Calculate the speed of the train as it passes C, giving your answers to one decimal place. [3]

I would appreciate if you could show me how to answer, as well as providing the answer. I don't see my maths teacher until next week when the homework is due, so I would like help beforehand so I don't fall behind. I know to use the SUVAT equations but I don't know how to for this question.

I don't want to cheat my homework - only just to see how to answer. That's all. Thank you!

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(Original post by

Start by considering the motion from A to B only. Which of the SUVAT variables do you have for this motion?

**Sir Cumference**)Start by considering the motion from A to B only. Which of the SUVAT variables do you have for this motion?

T = 60s?

I'm not too sure here. That's why I asked for help.

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#4

It's fine if you're not sure. I'm guiding you through the problem.

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(Original post by

That's correct but you also have 'V' given to you in the question. Can you see what it is?

It's fine if you're not sure. I'm guiding you through the problem.

**Sir Cumference**)That's correct but you also have 'V' given to you in the question. Can you see what it is?

It's fine if you're not sure. I'm guiding you through the problem.

Thanks for helping me by the way. Much appreciated!

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#6

S = 1200

U = ?

V = 26

A = ?

T = 60

Ok so for part a) you need to find the SUVAT variable 'U' so the next step is to consider all of the SUVAT equations and find one that doesn't have 'A' in it (because we don't know that yet). Then you should be able to use the equation you choose to find 'U'. Does that help?

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(Original post by

Yes that's right. Now as soon as you have three of the SUVAT variables, that's enough to find all the others. Here you have

S = 1200

U = ?

V = 26

A = ?

T = 60

Ok so for part a) you need to find the SUVAT variable 'U' so the next step is to consider all of the SUVAT equations and find one that doesn't have 'A' in it (because we don't know that yet). Then you should be able to use the equation you choose to find 'U'. Does that help?

**Sir Cumference**)Yes that's right. Now as soon as you have three of the SUVAT variables, that's enough to find all the others. Here you have

S = 1200

U = ?

V = 26

A = ?

T = 60

Ok so for part a) you need to find the SUVAT variable 'U' so the next step is to consider all of the SUVAT equations and find one that doesn't have 'A' in it (because we don't know that yet). Then you should be able to use the equation you choose to find 'U'. Does that help?

Equation would be:- S=1/2(u+v)t, right?

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#8

(Original post by

Yes, it does help. Thanks a lot. I'll let you know how I get on!

Equation would be:- S=1/2(u+v)t, right?

**ryanjj14**)Yes, it does help. Thanks a lot. I'll let you know how I get on!

Equation would be:- S=1/2(u+v)t, right?

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#9

You could make an equation for a, which is (v-u)/t. You have v = 26 m s-1, t = 60 s, so a=(26 - u)/60

Now substitute that in s = ut + 0.5at^2

1200 = 60u + 0.5((26 - u)/60) × 60^2

1200 = 60u + ((26 - u)/120)×3600

1200 = 60u + (26 - u) × 30

1200 = 60u + 780 - 30u

u = (1200-780)/(60-30)

u = 14 m s-1

Then for finding a, just substitute the value of u.

And the final question, I think you could answer that now. (Answer is 40.9 m s-1)

P.S. I would suggest practising a lot cuz if you have trouble solving such a simple question.... it only gets harder thats all I'm saying. Sorry.

Now substitute that in s = ut + 0.5at^2

1200 = 60u + 0.5((26 - u)/60) × 60^2

1200 = 60u + ((26 - u)/120)×3600

1200 = 60u + (26 - u) × 30

1200 = 60u + 780 - 30u

u = (1200-780)/(60-30)

u = 14 m s-1

Then for finding a, just substitute the value of u.

And the final question, I think you could answer that now. (Answer is 40.9 m s-1)

P.S. I would suggest practising a lot cuz if you have trouble solving such a simple question.... it only gets harder thats all I'm saying. Sorry.

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(Original post by

Yes that's the one you should use.

**Sir Cumference**)Yes that's the one you should use.

My steps are:

1200 = 1/2 (u+26) x 60

1200 = 30 (u+26)

1200 = 30u + 780

1200-780 = 30u

420 = 30u

420/30 = u

u = 14ms-1

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#11

(Original post by

X

**SeverusESnape**)X

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#12

(Original post by

I've got an answer for U as 14ms-1. Would that be correct?

My steps are:

1200 = 1/2 (u+26) x 60

1200 = 30 (u+26)

1200 = 30u + 780

1200-780 = 30u

420 = 30u

420/30 = u

u = 14ms-1

**ryanjj14**)I've got an answer for U as 14ms-1. Would that be correct?

My steps are:

1200 = 1/2 (u+26) x 60

1200 = 30 (u+26)

1200 = 30u + 780

1200-780 = 30u

420 = 30u

420/30 = u

u = 14ms-1

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(Original post by

That's correct! Now try the next part.

**Sir Cumference**)That's correct! Now try the next part.

For the acceleration, I had 0.2ms-2.

My method was:-

a = v-u / t

a = 26-14 / 60

a = 12 / 60

a = 0.2ms-2

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#14

(Original post by

There was no need to post the full answer. Let them do the work themselves with hints.

**Sir Cumference**)There was no need to post the full answer. Let them do the work themselves with hints.

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#15

(Original post by

Okay, thanks so much.

For the acceleration, I had 0.2ms-2.

My method was:-

a = v-u / t

a = 26-14 / 60

a = 12 / 60

a = 0.2ms-2

**ryanjj14**)Okay, thanks so much.

For the acceleration, I had 0.2ms-2.

My method was:-

a = v-u / t

a = 26-14 / 60

a = 12 / 60

a = 0.2ms-2

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(Original post by

That's also correct!

**Sir Cumference**)That's also correct!

I used the formula: v^2 = u^2 + 2as

For SUVAT, I had s=2500m, u=26ms-1, v=?, a=0.2ms-2, t=?

I substituted them into the formula to find v and had the square root of 1676, which was 40.9ms-1.

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#17

(Original post by

Okay, thank you. For part c, I had 40.9ms-1 because it asked you to give your answer to 1 decimal place.

I used the formula: v^2 = u^2 + 2as

For SUVAT, I had s=2500m, u=26ms-1, v=?, a=0.2ms-2, t=?

I substituted them into the formula to find v and had the square root of 1676, which was 40.9ms-1.

**ryanjj14**)Okay, thank you. For part c, I had 40.9ms-1 because it asked you to give your answer to 1 decimal place.

I used the formula: v^2 = u^2 + 2as

For SUVAT, I had s=2500m, u=26ms-1, v=?, a=0.2ms-2, t=?

I substituted them into the formula to find v and had the square root of 1676, which was 40.9ms-1.

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#18

(Original post by

I'm sorry I didn't see all your posts. I'm new to this site literally created an account yesterday cuz had an m2 question. Could you help me with that btw?

**SeverusESnape**)I'm sorry I didn't see all your posts. I'm new to this site literally created an account yesterday cuz had an m2 question. Could you help me with that btw?

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(Original post by

Correct.

**Sir Cumference**)Correct.

Thanks again! The next Q is a velocity-time graph.

Kind regards :-)

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#20

**SeverusESnape**)

I'm sorry I didn't see all your posts. I'm new to this site literally created an account yesterday cuz had an m2 question. Could you help me with that btw?

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