91Ó°ÊÓ

Problem 1

A mass of \(1.4 \mathrm{kg}\) of water at \(22^{\circ} \mathrm{C}\) is poured from a height of \(2.5 \mathrm{m}\) into a vessel containing \(5.0 \mathrm{kg}\) of water at \(22^{\circ} \mathrm{C} .\) (a) How much does the internal energy of the \(6.4 \mathrm{kg}\) of water increase? (b) Is it likely that the water temperature increases? Explain.

Problem 2

The water passing over Victoria Falls, located along the Zambezi River on the border of Zimbabwe and Zambia, drops about \(105 \mathrm{m} .\) How much internal energy is produced per kilogram as a result of the fall?

Problem 3

How much internal energy is generated when a \(20.0-\mathrm{g}\) lead bullet, traveling at \(7.00 \times 10^{2} \mathrm{m} / \mathrm{s},\) comes to a stop as it strikes a metal plate?

Problem 5

A child of mass \(15 \mathrm{kg}\) climbs to the top of a slide that is $1.7 \mathrm{m}\( above a horizontal run that extends for \)0.50 \mathrm{m}$ at the base of the slide. After sliding down, the child comes to rest just before reaching the very end of the horizontal portion of the slide. (a) How much internal energy was generated during this process? (b) Where did the generated energy go? (To the slide, to the child, to the air, or to all three?)

Problem 6

A 64 -kg sky diver jumped out of an airplane at an altitude of $0.90 \mathrm{km} .$ She opened her parachute after a while and eventually landed on the ground with a speed of \(5.8 \mathrm{m} / \mathrm{s} .\) How much energy was dissipated by air resistance during the jump?

Problem 7

During basketball practice Shane made a jump shot, releasing a \(0.60-\mathrm{kg}\) basketball from his hands at a height of \(2.0 \mathrm{m}\) above the floor with a speed of \(7.6 \mathrm{m} / \mathrm{s}\) The ball swooshes through the net at a height of \(3.0 \mathrm{m}\) above the floor and with a speed of \(4.5 \mathrm{m} / \mathrm{s}\). How much energy was dissipated by air drag from the time the ball left Shane's hands until it went through the net?

Problem 8

An experiment is conducted with a basic Joule apparatus, where a mass is allowed to descend by \(1.25 \mathrm{m}\) and rotate paddles within an insulated container of water. There are several different sizes of descending masses to choose among. If the investigator wishes to deliver \(1.00 \mathrm{kJ}\) to the water within the insulated container after 30.0 descents, what descending mass value should be used?

Problem 9

Convert \(1.00 \mathrm{kJ}\) to kilowatt-hours \((\mathrm{kWh})\).

Problem 12

If \(125.6 \mathrm{kJ}\) of heat are supplied to \(5.00 \times 10^{2} \mathrm{g}\) of water at \(22^{\circ} \mathrm{C},\) what is the final temperature of the water?

Problem 13

It is a damp, chilly day in a New England seacoast town suffering from a power failure. To warm up the cold, clammy sheets, Jen decides to fill hot water bottles to tuck between the sheets at the foot of the beds. If she wishes to heat \(2.0 \mathrm{L}\) of water on the wood stove from $20.0^{\circ} \mathrm{C}\( to \)80.0^{\circ} \mathrm{C},$ how much heat must flow into the water?