Why should the safety net that is used in circuses under trapezoids be little tightened?

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."

10 newton object is placed 3 meters from the fulcrum. at what distance on the other side would you need to place a 15 newton object to balance the lever? show your work!

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z