Is a Skydiver at Terminal Velocity an Inertial Reference Frame?

[Soaring Crane]

1) Which object provides an inertial frame of reference?

a. the tip of the moving second hand of a clock
b. a rock thrown vertically upward
c. a pendulum swinging with no air resistance
d. a skydiver falling at terminal velocity

At first I thought c might be correct, but now I am confused. The Earth is a reference frame?

2) You are conducting an experiment inside an elevator that can move in a vertical shaft. A load is hung vertically from the ceiling on a string. The tension in the string is measured to be 10% less than the weight of the load. No other forces are acting on the load. Which of the following statements about the elevator are correct? (> 1 can be correct)

A.The elevator is an inertial frame of reference.
B.The elevator is not an inertial frame of reference.
C.The elevator may be at rest.
D.The elevator may be moving at a constant velocity upward.
E.The elevator may be moving at a constant velocity downward.
F.The elevator must be accelerating.

I think A, C, D, E may be correct, but I am not sure.

Thanks.

 

[Physics is Phun]

an inertial frame of reference is anything not accelerating.
I don't have time for # 2. sorry.

 

[wais]

1) The correct answer is d. A skydiver falling at terminal velocity provides an inertial frame of reference. This is because at terminal velocity, the skydiver is falling at a constant velocity, meaning there is no acceleration and therefore no net force acting on the skydiver. This allows for the skydiver to be used as a reference point for other objects in motion.

2) The correct answers are A, D, and E. The elevator is an inertial frame of reference because there are no external forces acting on the load, meaning it is moving with a constant velocity. The elevator may be at rest or moving at a constant velocity upward or downward, all of which are still considered inertial frames of reference. The elevator does not have to be accelerating, so F is not a correct answer.