Calculate the force that produced this acceleration. 2. Calculate the force required to stop the car.

$$F = ma$$ $$F = (2300 \text{ kg}) \times (5 \frac{\text{m}}{\text{s}^2})$$ $$F = 11500 \text{ N}$$

The force produced is $\boxed{\text{11500 N}}$.

2. Calculate the force required to stop the car.

The car stops, so the final velocity $v = 0 \frac{\text{m}}{\text{s}}$.

$$v = u + at$$ $$0 \frac{\text{m}}{\text{s}} = 25 \frac{\text{m}}{\text{s}} + a(2 \text{ s})$$ $$-25 \frac{\text{m}}{\text{s}} = a(2 \text{ s})$$ $$a = \frac{-25 \frac{\text{m}}{\text{s}}}{2 \text{ s}}$$ $$a = -12.5 \frac{\text{m}}{\text{s}^2}$$

$$F = ma$$ $$F = (2000 \text{ kg}) \times (-12.5 \frac{\text{m}}{\text{s}^2})$$ $$F = -25000 \text{ N}$$

The negative sign indicates that the force is in the opposite direction of the car's motion, which is expected for a braking force. The magnitude of the force required is $\boxed{\text{25000 N}}$.