What force is needed to accelerate a car

AI Thread Summary
To determine the force needed to accelerate a 1200kg vehicle from rest to 108km/hr over 100m, the acceleration and time must be accurately calculated. The final velocity converts to 30 m/s, and using the distance, the time is found to be approximately 3.33 seconds. However, the acceleration calculation is incorrect, as the vehicle does not maintain a constant velocity throughout the distance. The correct approach requires using the average velocity or integrating acceleration over time. The confusion about converting mass to Newtons by multiplying by gravity highlights the need for clarity in applying the force equation.
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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?
 
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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.
 

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