#### Answer

The average net force exerted on the car and riders by the magnets is equal to $3.5 \times 10^4N$.

#### Work Step by Step

1. Find the acceleration of the car and its riders.
$v = v_0 + at$
** They started at rest, so $v_0 = 0$
$v = at$
$45m/s = a \times (7.0s)$
Divide both sides by 7.0s:
$\frac{45m/s}{7.0s} = a$
$a = 6.4 m/s^2$
2. Calculate the net force exerted on the car and riders:
$F=ma$
$F = (5.5\times10^3kg)(6.4m/s^2)$
$F = 3.5 \times 10^4 \frac{kg*m}{s^2} = 3.5 \times 10^4 N$