In about 13,000 years, our summers in the northern hemisphere will be in december and our winters will be in june. this change is due to a. an increase in earths rotation rate b. increasing fall equinoxes c. precession d. an increase in earths revolution rate

Suppose that a cylindrical tank 6 meters high with a radius of 2 meters is filled to the rim with water. the tank is buried so that the top of the tank is 1 meter below ground level. the space above the tank is not filled with water. calculate how much work needs to be done by a pump to pump the water out of the tank up to ground level. (the water weighs 9,800 newtons per cubic meter.)