You are riding a skateboard down a gradual incline. In order to waste as little energy as possible while still maintaining control over your direction of motion, the contact between the sidewalk and the wheels should experience
A. only static friction.
B. no friction.
C. both static and sliding friction.
D. only sliding friction.
Answer:A
You are riding a skateboard down a gradual incline. In order to waste as little energy as possible while still maintaining control over your direction of motion, the contact between the sidewalk and the wheels should experience
A. only static friction. B. no friction. C. both static and sliding friction. D. only sliding friction.