posted by robert .
A 300. kg roller coaster car is traveling at a constant speed of 15 m/s over a hill with a radius of curvature of 30. m.
b. What is the normal force acting on the car at the top of the hill?
c. Assume that the car is at the intersection of the radius and the hill and that a frictional force exists between the car and the hill. Draw a force diagram showing all forces.
10. A child twirls his yo-yo horizontally about his head rather than using it properly. The yo-yo has a mass of 0.250 kg and is attached to a string 0.800 m long.
a. If the yo-yo makes a complete revolution each second, what tension must exist in the string?