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M2 power tractive force question

apparently the answer is 45ms-1 for part 1, but I cannot get that answer.

What I do is use p=fv to get p=15*f
get f as 0.2*9.8*1000+100
this gets a power of 30900 which doesn't work.

;( apparently there is no hope then...

(edited 7 years ago)

Reply 1

tavtavtav

nvm, after an hour I've just noticed i've been had by weight / mass misinterpretation...

edit: Incase anyone sees this thread and wants to solve the question (so the thread isn't a total waste):

P=fv
p=15f
at maximum speed, acceleration = 0 and tractive force = total resistance.
f = mgsin(theta) + R
f = 1000(9.8)(0.2) + (1/10)(1000)(9.8) = 2940
p = 2940*15 = 44100

On flat ground P=fv so 44100 = fv
f=R
f = (1/10)(1000)(9.8) = 980
44100/980 = 45m/s

(edited 7 years ago)

Reply 2