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# Multiple choice As Physics AQA question Help needed. watch

1. A car exerts a driving force of 500N when travelling at a constant speed of 72 KMH-1 on a level track. What is the work done in 5 minutes??

According to the marksceme the answer is 2.0x10^5

Can someone explain how to get that that answer. Thanks !
2. I don't get that answer, what I get is :-

Work done = Force * Distance.

Distance travelled = speed * time = 72 * (5/60) = 6km = 6000m

So, Work done - 500N * 6000m = 3x10^6 Nm

Is that what you've been getting?
3. 72 km h^-1 = 20 m s^-1

in 300 secs the car travels 6000 m

over that distance the car is exerting constant 500N force

work done = Fs

500 x 6000 = 3x10^6 J
4. 72KmH-1 = 20m/s

P=FV
20*500= 10,000W
PT=E
(5mins= 300 secs)
10,000*300= 3x10^6J
5. fwiw MS says 3.0 x 10^6 J too

Q23 in paper http://filestore.aqa.org.uk/resource...081-SQP.PDF#24

answer to 23 is A (3.0 x 10^6 J)
in MS http://filestore.aqa.org.uk/resource...081-SMS.PDF#13
6. I think you've been reading the wrong bit of the mark scheme Kraixo - the answer is A - 3x10^6J

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