Question

question 1
if we know an object is moving at constant velocity, we may assume
the net force acting on the object is zero.
there are no forces acting on the object.
the object is accelerating.
the object is losing mass.
question 2
a physics student is riding on a train traveling north. having read about inertia, the student performs an experiment with a golf ball. he reaches over the aisle and drops the ball from rest. instead of hitting the floor directly below the students hand, it hits to the north, i.e. forward of that position. which of the following might be the cause for this to happen?
the train is moving at constant velocity.
the train is speeding up.
the train is slowing down.
whatever the cause, it cannot be any of the answers given.

Explanation:

For Question 1, according to Newton's first - law, an object moving at constant velocity has a net force of zero acting on it. There can be forces acting on it, but they balance out. Acceleration is zero for constant velocity, and there is no indication of mass change.
For Question 2, when the train is slowing down while moving north, the golf ball, due to inertia, will continue to move with the initial velocity it had when dropped and will move forward (north) relative to the position directly below the hand as the train's velocity decreases.

Answer:

Question 1: the net force acting on the object is zero
Question 2: The train is slowing down