Black holes result from

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative