Methods to reduce the frictional force between the an object and surface which it is in contact.

Imagine you are riding on a yacht in the ocean and traveling at 20 mph. you then hit a golf ball at 100 mph from the deck of the yacht. you see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph). now imagine you are aboard the hermes spacecraft traveling at 0.1c (1/10 the speed of light) past mars and shine a laser from the front of the ship. you would see the light traveling at c (the speed of light) away from your ship. according to einstein’s special relativity, how fast will a person on mars observe the light to be traveling? a) 0.1c (1/10 the speed of light) b) c (the speed of light) c)1.1c (c+0.1c)

World class speed skaters can skate a 3,000-m course in about 4 minutes.what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s

If the spring constant k of a pogo stick is 3500 n m and the weight of the person on the pogo stick is 700 n, how much is the spring in the botom of the pogo stick compressed?