Answer:
(a) 
, 
(b) When 
, object is slowing down, when 
object is speeding up.
Explanation:
(a) To get the velocity function, we need to take the derivative of the position function.
To get the acceleration function, we need to take the derivative of the velocity function.
(b) The object is slowing down when velocity is decreasing by time (decelerating) hence a < 0
On the other hand, object is speeding up when a > 0
Therefore, when 
, object is slowing down, when object is speeding up.
Answer:
C. Weight is mass times the acceleration of gravity.
Explanation:
Weight is the force exerted by gravity. Force is equal to mass times acceleration.
While skydiving, its not just freely falling under Earth's gravity. Additional force called drag acts against the gravity which slows down the rate of fall. Drag is caused by the air molecules which pushes against the body as it falls through them. This is actually a significant amount of force which slows down the rate of fall of the body. Drag depends on the contact surface area and weight. More the surface area in contact, more would be the drag. The sitting position of the skydiver would experience less drag than the chest down position because of the less contact surface area of the body with the air molecules while in the former case. No two persons have identical body shape and weight. Hence, the rate of fall can be made nearly equal but not exactly equal. This is would be possible when they are having same body position.
The answer would be C: Rheostat. :)
Answer:
velocity =displacement/time
and speed =distance/time
