Question

The additional force needed to maintain the speed o pickup truck at constant 20 m/s when rain begins to all and accumulates in its back at a rate o 3.0 kg/min is
a. 0
b. 1 N
c. 10 N
d. 60 N

Answer 1

In one second, 0.05 kg of mass is added. Suppose we can accelerate for one second and need to get that new mass up to 20 m/s. The acceleration is 20 m/s^2.

Now using that and F = ma, you have your answer.