Answer
$500 \frac{m}{s^{2}}$. 1.5 N. 1.5 N.
Work Step by Step
a. The acceleration is the change in velocity divided by the time interval.
$$a = \frac{25 m/s-0}{0.05 s} = 500 \frac{m}{s^{2}}$$
b. Use Newton's second law.
$$F = ma = (0.003 kg)(500 \frac{m}{s^{2}}) = 1.5 N$$
c. By Newton’s third law, the same amount, 1.5 N.