A lazy penguin slides down a snow-covered slope on its chest. Suppose that the diagonal length of the slope is 12 m, and it is inclined at an angle of 10o above the horizontal. If the penguin is traveling at 4 m/s when it reaches the bottom of the slope, what is the coefficient of friction between the penguin and the slope? .... this problem twice: once with Newton's second law and kinematics, and once with energy methods with a few sentences comparing the approaches