A 65 kg cyclist on a 15 kg bicycle starts from rest and increases his speed to 12 m/s in 20. s. a) What is the power output?

b) If the cyclist provided an average power of 400 W, what is the efficiency of the bicycle?

The total amount of energy contained in an object

Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? a. the first law describes how thermal energy is conserved but not the direction it moves. b. the first law describes the direction thermal energy moves but not how it is conserved. c. the first law describes how thermal energy can be created but not how it can be destroyed. d. the first law describes how thermal energy can be destroyed but not how it can be created.

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?