2. A ball of mass 0.50 kg is attached to a horizontal spring. The spring is compressed 0.25 m from its equilibrium and then released. The ball undergoes simple harmonic motion, achieving a maximum speed of 1.5 m/s. (a) Determine the spring constant. (b) Calculate the speed of the ball when the spring is halfway to its equilibrium point. (c) When the ball is halfway to its equilibrium point, what fraction of its energy has been converted from elastic potential energy to kinetic energy? Full solution 1. A sport utility vehicle, of mass 2.1x 103kg, travels in the horizontal plane around an unbanked curve of radius 275 m at a speed of 26 m/s, without sliding. (a) Determine the minimum coefficient of static friction between the tires and the road. (b) How would your answer in (a) be affected if the mass of the vehicle were greater because of the presence of heavy cargo? (c) How would your answer in (a) be affected if the curve were sharper (i.e., if its radius were smaller)