Physical Science

when 20 kJ of heat are removed from 1.2 kg of ice originally at -5 C, its new temperature is

-23 C

Oxygen boils at -183 C. The Fahrenheit equivalent of this temperature is

-297 F

a frictionless heat engine can be 100 percent efficient only if its exhaust temperature is

0 K

An object suspended from a spring scale is lowered into a pail filled to the brim with water, and 4 N of water overflows. The scale shows that the object weighs 6 N in the water. The weight in air of the object is

10 N

when 400 kJ of heat is added to 12 kg of water at 2 C, its final temperature is

17.9 C

a 2-kg brick has the dimensions 7.5 cm X 14 cm X 30 cm. The pressure the brick exerts when standing on its smallest face is

178 Pa

A wooden plank 200 cm long, 30 cm wide, and 40 mm thick floats in water with 10 mm of its thickness above the surface. The mass of the board is

18 kg

If the pressure on 10 m^3 of air is increased from 200 kPa to 800 kPa, the new volume of air will be

2.5 m^3

An ideal frictionless engine absorbs heat at 400 K and exhausts heat at 300 K. Its efficiency is

25 percent

At which of the following temperatures would the molecules of a gas have twice the average kinetic energy they have at room temperature, 20 C

313 C

a 3-kg pine board is 20 cm wide, 2 cm thick, and 2 m long. The density of the board is

375 kg/m^3

If a heat engine that exhausts heat at 400 K is to have an efficiency of 33 percent, it must take in heat at a minimum of

449 K

The Celsius equivalent of a temperature of 120 F is

49 C

Lead melts at 330 C. On the absolute scale this temperature corresponds to

603 K

the physics of a refrigerator most closely resembles the physics of

a heat engine

which of the following statements is not correct a) matter is composed of tiny particles called molecules b) these molecules are in constant motion, even in solids c) all molecules have the same size and mass d) the difference between the solid, liquid, and gaseous states of matter lie in the relative freedom of motion of their respective molecules

all molecules have the same size and mass

A person stands on a very sensitive scale and inhales deeply. The reading on the scale a) increases b) does not change c) decreases d) any of the above, depending on how the expansion of the person's chest compares with the volume of air inhaled

any of the above, depending on how the expansion of the person's chest compares with the volume of air inhaled

molecular motion is not responsible for

buoyancy

one gram of steam at 100 C causes a more serious burn than 1 g of water at 100 C because the steam

contains more energy

in any process, the maximum amount of heat that can be converted to mechanical energy

depends on the intake and exhaust temperatures

the working substance (or refrigerant) used in most refrigerators is a

gas that is easy to liquify

the temperature of a gas sample in a container of fixed volume is raised. The gas exerts a higher pressure on the walls of its container because its molecules

have higher average velocities and strike the walls more often

in any process, the maximum amount of mechanical energy that can be converted to heat

is 100 percent

when a vapor condenses into a liquid,

it gives off heat

At constant pressure, the volume of a gas sample is directly proportional to

its absolute temperature

on the molecular level, heat is

kinetic energy

the volume of a gas sample is increased while its temperature is held constant. The gas exerts a lower pressure on the walls of its container because its molecules strike the walls

less often

The density of freshwater is 1.00 g/cm^3 and that of seawater is 1.03 g/cm^3. A ship will float

lower in freshwater than in seawater

Two thermometers, one calibrated in F and the other in C, are used to measure the same temperature. The numerical reading on the F thermometer

may be any of these, depending on the temperature

absolute zero may be regarded as that temperature at which

molecular motion in a gas would be the minimum possible

a refrigerator gives off

more heat than it absorbs from its contents

buoyancy occurs because, as the depth in a fluid increases, the fluid's

pressure increases

heat transfer in a vacuum can occur by

radiation only

heat transfer in a gas can occur by

radiation, convection, and conduction

an ice cube whose center consists of liquid water is floating in a glass of water. When the ice melts, the level of water in the glass

remains the same

a heat engine takes in heat at one temperature and turns

some of it into work and rejects the rest at a lower temperature

the pressure of the earth's atmosphere at sea level is due to

the gravitational attraction of the earth for the atmosphere

food cooks more rapidly in a pressure cooker than in an ordinary pot with a loose lid because

the high pressure raises the boiling point of water

the greater the entropy of a system of particles,

the less the order of the system

at a given temperature

the molecules in a gas all have the same average energy

when evaporation occurs, the liquid that remains is cooler because

the slowest molecules remain behind

the second law of thermodynamics does not lead to the conclusion that

the total amount of energy in the universe, including rest energy, is constant

the fluid at the bottom of a container is

under more pressure than the fluid at the top

heat is absorbed by the refrigerant in a refrigerator when it

vaporizes

when 1 kg of steam at 200 C loses 3 MJ of heat, the result is

water and ice