How long will it take a 100w motor to lift a 5kg mass 20m?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

Robin is swinging back and forth from a trapeze. in which of the following situations is his kinetic energy being transformed into potential energy

For two variables in a direct proportion, what is the result of doubling one variable?