Holden is trying to determine the velocity of his race car. He went 20 meters east, turned around, and went 40 meters west. His car was 20 meters from the starting line. This took 5 seconds. What is the car’s average velocity? A. 4 m/s east
B. 4 m/s west
C. 12 m/s west
D. 12 m/s east

Aplayground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. a 63.0-kg child, initially at the top, slides all the way down to the bottom of the slide. (a) choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? what is the change in potential energy as the child slides from the top to the bottom of the slide? (include the sign of the value in your answer.)