10. A yo-yo hangs from a string of 0.25 m in length. A person holds the free end of the string and swings the yo-yo around in a circle. It makes one rotation every 0.50 s. What is the average speed of the yo-yo?

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. it strikes a red glider that has mass 0.600 kg and that is initially at rest. after the collision, the blue glider is moving to the left with a speed of 3.00 m/s.(a) what are the magnitude and direction of the velocity of the red glider after the collision? (b) is this collision elastic?