# Angular acceleration

A racing car accelerates from 50 km per hour to 200 km per hour in 3.0 seconds along a straight track, and the acceleration is constant during this period. If the axles are 40 cm above the road, what is the magnitude of the angular acceleration of the wheels?

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1. well, in each rotation of the wheel, the wagon goes 2PI*r
speed car=2PIr/timeforonerotation=w*r
w=speedcar/r so change those speed in km/hr to m/s, find wi and wf

angacceleration= (wf-wi)/3sec

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bobpursley
2. So 200km/h is 55.5 m/s and 50km/h is 13.75 m/s.

Wi=55.5/0.4=138.75
Wf=13.75/0.4=34.36

(138.75-34.36)/3= 34.7

Thanks bob. I think this is correct, forgive my lack of units.

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