You are Here: Home >< Maths

# M1 Modelling using constant acceleration Help with attached PDF. Watch

1. Hi Mathmaticians I need help with this Question.

A car starts at rest at 2ms^-2 for 4 seconds. It thens travels at constant speed for 10 minutes. How far has it travelled in this time.

I don't understand why a=0 during the last stage of the journey.

Attached Images
2. 09041302.PDF (224.9 KB, 61 views)
3. (Original post by WorkHardNow)
Hi Mathmaticians I need help with this Question.

A car starts at rest at 2ms^-2 for 4 seconds. It thens travels at constant speed for 10 minutes. How far has it travelled in this time.

I don't understand why a=0 during the last stage of the journey.

"constant speed" means acceleration = 0 (well, assuming straight-line motion )
4. (Original post by WorkHardNow)
Hi Mathmaticians I need help with this Question.

A car starts at rest at 2ms^-2 for 4 seconds. It thens travels at constant speed for 10 minutes. How far has it travelled in this time.

I don't understand why a=0 during the last stage of the journey.

If it travels at constant speed the acceleration is 0
5. (Original post by gdunne42)
If it travels at constant speed the acceleration is 0
Also if deceleration is constant is a=0 also.
6. (Original post by WorkHardNow)
Also if deceleration is constant is a=0 also.
Deceleration is just negative acceleration.

And no, it's not zero.

a=0 implies there is no acceleration and no deceleration.

If there is any acceleration or deceleration, then a does not equal 0.
7. (Original post by ghostwalker)
Deceleration is just negative acceleration.

And no, it's not zero.

a=0 implies there is no acceleration and no deceleration.

If there is any acceleration or deceleration, then a does not equal 0.
I'm not sure what you mean because it says there is constant speed.
8. (Original post by WorkHardNow)
I'm not sure what you mean because it says there is constant speed.
If there is constant speed, then acceleration and deceleration are both zero.

But that wasn't the question you asked.
9. (Original post by ghostwalker)
If there is constant speed, then acceleration and deceleration are both zero.

But that wasn't the question you asked.
Yh this is a different question because I was doing an Exam question and it said A car is traveling along a straight road with initial speed of 11 ms^-1 when it starts to slow down at a traffic light. Its deceleration is constant. The car stops after three seconds, waits for 5 seconds and then accelerates uniformly to its original speed of 11 ms^-1 in 4 seconds.
10. (Original post by WorkHardNow)
Yh this is a different question because I was doing an Exam question and it said A car is traveling along a straight road with initial speed of 11 ms^-1 when it starts to slow down at a traffic light. Its deceleration is constant. The car stops after three seconds, waits for 5 seconds and then accelerates uniformly to its original speed of 11 ms^-1 in 4 seconds.
Well here you're interested in from when the car starts to decelerate. When it's decelerating "a" will not equal zero, the car is slowing down, velocity is not constant.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 10, 2013
Today on TSR

### Should I ask for his number?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE