What force is needed to accelerate a car

[smarties]

Homework Statement

What force is needed to make a 1200kg vehicle accelerate from rest to 108km/hr in 100m

Homework Equations

aceleration = Velocity/time

Force = Mass x Acceleration

Time = Distance/Velocity

The Attempt at a Solution

M = 1200kg

D = 100m

V = 108 km/hr / 3.6 = 30 m/s

t = 100m/30 m/s = 3.33sec

a = 30 m/s / 3.33sec = 9 m/s

F = 1200 x 9 m/s = 10800kg

Now do I need to convert the kg to Newtons? by multiplying by gravity 9.8m/s I am a bit confused about that?

 

[danago]

Be careful with how you calculated the time of the trip.

You used t=s/v, but that equation is for the case when the acceleration is zero.

The velocity of the car isn't 30m/s for the whole trip, only at the end.