Calculate the percent efficiency of a fan that uses 2400 J of energy to generate 1300 J of kinetic energy. (use GRASP)

You throw a small rock straight up from the edge of a highway bridge that crosses a river. the rock passes you on its way down, 7.00 s after it was thrown. what is the speed of the rock just before it reaches the water 28.0 m below the point where the rock left your hand? ignore air resistance.

The flame produced by the burner of a gas (propane) grill is a pale blue color when enough air mixes with the propane (c3h8) to burn it completely. for every gram of propane that flows through the burner, what volume of air is needed to burn it completely? assume that the temperature of the burner is 195.0°c, the pressure is 1.05 atm, and the mole fraction of o2 in air is 0.210.

Describe the work performed by a ski lift in terms of kinetic and gravitational potential energy