A sled is being held at rest on a slope that makes an angle theta with the horizontal. After the sled is released, it slides a distance d1 down the slope and then covers the distance d2 along the horizontal terrain before stopping. Which assumptions are reasonable to make in this problem? There can be more than one answer.
B) The sled can be treated as a particle moving with constant acceleration (not necessarily the same acceleration in both parts).
C) The sled cannot be treated as a particle.
D) The air resistance is substantial.
E) The air resistance is negligible.
F) The amount of heat generated is substantial.
G) The amount of heat generated is negligible.
I) The force of friction is different for different parts of the motion.
J) The sled is the only object in the system.
K) The sled and slope are both part of the system.
a) Obviously not true; the velocity changes. At first the velocity increases as the sled slides down the hill, then the velocity decreases as the sled comes to a stop.
b) True for the reasons given above.
c) Any point on the sled can be treated as a particle. The whole sled cannot be treated as a particle. This is ...
Reasoning is provided to support the answer.