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M1 Modelling using constant acceleration Help with attached PDF.

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.

Thank you in advance
09041302.PDF230.3KB
Reply 1
Avatar for davros
davros
16
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.

Thank you in advance


"constant speed" means acceleration = 0 (well, assuming straight-line motion :smile:)
Reply 2
Avatar for gdunne42
gdunne42
21
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.

Thank you in advance


If it travels at constant speed the acceleration is 0
Reply 3
Avatar for WorkHardNow
WorkHardNow
OP
Original post by gdunne42
If it travels at constant speed the acceleration is 0


Also if deceleration is constant is a=0 also.
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.
Reply 5
Avatar for WorkHardNow
WorkHardNow
OP
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.
(edited 11 years ago)
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.
Reply 7
Avatar for WorkHardNow
WorkHardNow
OP
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.
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.

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