An inventor develops a stationary cycling device by which an individual, while pedaling, can convert all of the energy expended into heat for warming water. what minimum power must be generated if 210 g water (enough for 1 cup of coffee) is to be heated in 14.0 min from 26.0°c to 84.0°c? (1 cal = 4.186 j, the specific heat of water is 4 186 j/kg⋅°c)

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

When a bicycle coasts uphill, it moves slower and slower as it climbs. why? a. its kinetic energy is transforming into heat energy. b. its potential energy is transforming into kinetic energy. c. its kinetic energy is transforming into potential energy and heat energy. d. its potential energy is transforming into kinetic energy and heat energy.

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant