Question

a cup of coffee is sitting on a table in a recreational vehicle (rv). the cup slides toward the rear of the rv. according to newtons first law, which one or more of the following statements could describe the motion of the rv? (a) the rv is at rest, and the driver suddenly accelerates. (b) the rv is moving forward, and the driver suddenly accelerates. (c) the rv is moving backward, and the driver suddenly hits the brakes.
a. a
b. b
c. c
d. a and b
e. a, b, and c

Explanation:

Newton's first law states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. When the RV is at rest and the driver accelerates, the coffee - cup has inertia and tends to stay in place relative to the initial state, so it slides towards the rear. When the RV is moving forward and the driver accelerates, the coffee - cup's inertia makes it seem to slide towards the rear relative to the accelerating RV. When the RV is moving backward and the driver hits the brakes (decelerates), the coffee - cup due to inertia continues moving backward relative to the now - slowing RV and also slides towards the rear.

Answer:

E. A, B and C