An LRT train consisting of 4 cars is crossing the bridge from the U of A to downtown Cars 1, 2 and 3 all have a mass of 4.0*10^ 4 kg Car 4 has more passengers , so it has a mass of 4.5*10^ 4 kg . The train accelerates as it crosses the bridge at a rate of 0.25 m/s ^ 2 , north . Determine the force that car 4 exerts on car 3 during this period (/4)