You are mountain biking through the woods and come to a deep gully. The bottom of the gully is a smooth bowl shape without any obstacles. Neglecting friction and air resistance, you are able to coast down one side and back up the other without pedaling. When you are at the bottom of the gully, you feel
A. heavier than normal since you are accelerating upward.
B. lighter than normal since you are accelerating upward.
C. no heavier or lighter than normal since you are not accelerating at the bottom.
D. heavier than normal since you are accelerating downward.
Answer:A
You are mountain biking through the woods and come to a deep gully. The bottom of the gully is a smooth bowl shape without any obstacles. Neglecting friction and air resistance, you are able to coast down one side and back up the other without pedaling. When you are at the bottom of the gully, you feel
A. heavier than normal since you are accelerating upward. B. lighter than normal since you are accelerating upward. C. no heavier or lighter than normal since you are not accelerating at the bottom. D. heavier than normal since you are accelerating downward.