What would happen to the marbles speed if we had longer tables

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

On your wedding day your lover gives you a gold ring of mass 3.67 g. 48 years later its mass is 3.44 g. on the average how many atoms were abrated from the ring during each second of your marriage? the atomic mass of gold is 197 u. don't enter units

What causes the development of most clouds and precipitation in the atmosphere?