A marble is allowed to roll down an inclined plane from a fixed height. At the foot of inclined plane, it moves on horizontal surface. a) Covered with silk b) Covered with a layer of sand c ) Covered with glass sheet . On which surface marbles move the shortest distance. Give reason for your answer.

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?