The temperature u in a metal ball is proportional to the square of the distance from the center of the ball. Find the rate of heat flow across a sphere S of radius r with center at the center of the ball. SOLUTION Taking the center of the ball to be the origin, we have u(x, y, z)

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.

An ice-making machine inside a refrigerator operates in a carnot cycle. it takes heat from liquid water at 0.0 degrees celsius and rejects heat to a room at a temperature of 19.2 degrees celsius. suppose that liquid water with a mass of 76.3kg at 0.0 degrees celsius is converted to ice at the same temperature. take the heat of fusion for water to be l_f = 3.34*10^5 j/kg. how much energy e must be supplied to the device? express your answer in joules.

Your friend increases her force on the desk by 30n . she doesn't change the direction of her push . what happens to the net force on the desk .will the desk accelerate