[M2] - Edexcel Jan '03 - Question 2 Watch

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MdSalih
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#1
Report Thread starter 14 years ago
#1
Having a problem with this... my answer seems to be out by a tenth

The question is as follows:

A car of mass 1000 kg is moving along a straight horizontal road with a constant acceleration of f ms^2. The resistance to motion is modelled as a constant force of magnitude 1200 N. When the car is travelling at 12 ms^1, the power generated by the engine of the car is 24 kW.

(a) Calculate the value of f.
This is my working for it:

Power = Driving Force * Speed

=> 24000 = F * 12
=> F = 2000

So Force output by car is 2000 N

Then by N2L:

Force = Mass * Acceleration

=> 2000 - 1200 = 1000a
=> 0.8 = a

So acceleration of the car is 0.8 ms^2

Now in the answers it says its 0.08

So where have I gone wrong?

MdSalih
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Aitch
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#2
Report 14 years ago
#2
(Original post by MdSalih)
Having a problem with this... my answer seems to be out by a tenth

The question is as follows:



This is my working for it:

Power = Driving Force * Speed

=> 24000 = F * 12
=> F = 2000

So Force output by car is 2000 N

Then by N2L:

Force = Mass * Acceleration

=> 2000 - 1200 = 1000a
=> 0.8 = a

So acceleration of the car is 0.8 ms^2

Now in the answers it says its 0.08

So where have I gone wrong?

MdSalih
Looks Ok at first glance.

Aitch
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r_perry
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#3
Report 14 years ago
#3
(Original post by MdSalih)
Having a problem with this... my answer seems to be out by a tenth

The question is as follows:



This is my working for it:

Power = Driving Force * Speed

=> 24000 = F * 12
=> F = 2000

So Force output by car is 2000 N

Then by N2L:

Force = Mass * Acceleration

=> 2000 - 1200 = 1000a
=> 0.8 = a

So acceleration of the car is 0.8 ms^2

Now in the answers it says its 0.08

So where have I gone wrong?

MdSalih
Absolutely fine
Either the answer is wrong, the question is wrong Or maybe maths doesnt work
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