A 1200 kg vehicle initially travelling at 50. km/h experiences an air resistance of 5000 N and road friction of 2200 N. The wheels deliver a force of 7500 N to the vehicle. What is its acceleration?

The forces on the car are:

- - 7,500 N forward, from the engine

- - 5,000 N backwards, from air resistance

- - 2,200 N backwards, from road friction

The net force on the car is (+7,500 - 5,000 - 2,200) = 300 N forward.

Newton said: Force = (mass) x (acceleration)

Divide each side by (mass):

Acceleration = (force) / (mass)

Acceleration = (300 N) / (1,200 kg) = 0.25 m/s² forward.

Notice the big red herring at the beginning of the question:

It's nice to know that the vehicle starts out traveling at 50 km/hr,

but in order to answer this question, we honestly don't care!