Which is an example of physical weathering? a- limestone in rock dissolving when acid rain flows across it

b- bits of rock rusting when exposed to oxygen and water

c- wind blowing off bits of a rock over time

d- oxidation of certain metals in rock

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.