Electrical energy is used to spin the blades of a ceiling fan. If the electricity is cut off, the fan blades will slow down and eventually stop spinning. Why?

A.
All the kinetic energy of the fan blades has been transformed into potential energy.

B.
All the potential energy of the fan blades has been transformed into kinetic energy.

C.
All the kinetic energy of the fan blades has been transformed into heat energy.

D.
All the potential energy of the fan blades has been transformed into heat energy.

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 11.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.80 m/s; (b) he is then lifted at the constant speed of 4.80 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 78.0 kg rescue by the force lifting him during each stage

You are a sales representative for a company that makes a new alternate fuel for vehicles. you have prepared a presentation for the environmental engineers to sell your new product. what question do you expect the audience to ask regarding whether the new fuel will cause less damage to the environment? a. do we have to change any parts of the vehicle to use this alternate fuel? b. will the vehicles get better fuel mileage with the alternate fuel? c. how much greenhouse gas does your fuel produce compared with current fuel sources? d. is the alternate fuel more expensive than fossil fuel?

Which accurately compares concave and convex lenses?