You have a ball with mass 1.3 kg tied to a rope, and you spin it in a circle of radius 1.8 m. If the ball is moving at a speed of 3 m/s, what is the centripetal force acting on the ball?

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.