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forces problem - Please Help ASAP

A rear-wheel-drive car supports 48% of its weight on its two drive wheels and has a coefficient of static friction of 0.60.
(a) What is the vehicle's maximum acceleration?
(b) What is the shortest possible time in which this car can achieve a speed of 105 km/h? (Assume that the engine has unlimited power.)

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1 Answer

(a) Mass of car is m.    Fn = 0.48 * m*g.    Ffriction = 0.6 * Fn.   Now the maximum force the tires can exert will be Ffriction.   a= Ffriction/m   =    0.6 * 0.48 * m*g/ m =  2.82 m/s^2.

(b)  To find shorest time to accelerate to 105 km/h from rest.

Vf = V0 + a*t.   t =   Vf/a = (105 km/hr /2.82 m/s^2) * 1hr/3600s * 1000m/km = 10.3 s