10. A box of weight 135 N is attached to the end of a dangling spring, stretching the spring by 21.0 cm. What is the weight of an object that would stretch the spring by 69.6 cm?
11.A hockey puck is at rest on a flat surface. Then one end of the surface is lifted gradually, forming an inclined plane of increasing slope. If you know _____, you can accurately predict the angle at which the puck will start sliding. ( i got the answer choices)