A1000 kg car pushes a 2000 kg truck that has a dead battery. when the driver steps on the accelerator, the drive wheels of the car push against the ground with a force of 4500 n. what is the magnitude of the force of the car on the truck?

The answer is 3000 N.

Force (F) is the multiplication of mass (m) and acceleration (a).
F = m · a

It is given:
mc = 1000 kg
mt = 2000 kg
total force: F = 4500 N 
total mass: m = mc + mt

Let's calculate acceleration which is common:
a = F/m = F/(mc + mt) = 4500/(1000 + 2000) = 4500/3000 = 1.5 m/s²

Now, when we know acceleration, let's calculate force on the truck:
Ft = mt · a = 2000 · 1.5 = 3000 N