When an object rolls over a surface, the kind of friction that occurs is called
round friction
a. true
b. false

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?