PSC1121 MIDTERM REVIEW

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

At which of the following Celsius temperatures will a Fahrenheit thermometer show the same reading in degrees?

-40°C

A meter is not equal to

.001km

The shortest of the following is

.01mi

A centimeter is

0.01 m

A container holds 1 g of air at atmospheric pressure. When an additional gram of air is pumped into the container and there is no change in temperature, the new pressure is

2 atm

The size of a picture is given as 84 cm by 255 cm. Since (84)(255) = 2.142 exactly, the area of the picture is correctly expressed as

2.1 m 2.

The number of cubic centimeters in a cubic foot is about

2.8 × 10 4

If present trends in population and greenhouse gas emissions continue, the earth's surface temperature will increase by at least a catastrophic 4°C by the year

2100

A net force of 10 N gives an object an acceleration of 5 m/s 2. What net force would give the same object an acceleration of 1 m/s 2?

2N

A ball thrown upward at 30 m/s will continue to rise for about

2s

The minimum number of unequal forces whose vector sum can equal zero is

3

The power rating of an electric motor that draws a current of 3 A when operated at 240 V is

B. 720 W

Ethanol boils at 172°F. The Celsius equivalent of this temperature is

B. 78°C.

A weightlifter raises a 200-kg barbell through a height of 2 m in 2.2 s. The average power he develops during the lift is

C. 1.78 kW

A 400-kg concrete block is 1 m long, 0.6 m wide, and 0.3 m high. Its density is

C. 667 kg/m.

The scientist who showed that gravity accounts for Kepler's laws of planetary motion was

Newton

A week is the time needed for

None of the choices are correct

Which of these statements is not true for oil from tar sands?

Producing oil from tar sands involves emitting less carbon dioxide than extracting crude oil does.

Which of the following statements is not true?

Protons and electrons have the same mass

Which of the following formulas relating temperatures on the Celsius and Fahrenheit scales is correct?

Tc= 5/9 (Tf-32)

The earth's atmosphere is mainly heated by

infrared light radiated by the earth

The discovery that the planetary orbits are ellipses rather than circles was made by

kepler

The amplitude of a sound wave determines its

loudness

Of the following kinds of waves, the ones that cannot travel through a vacuum are

sound waves

Which of the following quantities is always the same to all observers?

the speed of light

What never changes when two or more objects collide is

the total momentum of all the objects

The primary coil of a transformer has 200 turns and its secondary coil has 50 turns, and the current in the secondary coil is 40 A. When a 12-V alternating current is applied to the primary coil of the transformer, the secondary voltage will be

3 v

When a ton of coal burns, it loses 3.3 × 10 -7 kg of mass. The energy given off is

3.0 × 10 10 J

When its brakes are applied, a car moving at 10 m/s undergoes an acceleration of -1.2 m/s 2. In the next 5 s the car travels

35M

The density of brass is 8 × 10 3 kg/m 3. The volume occupied by 320 g of brass is

38 cm 3

A car that starts from rest with a constant acceleration travels 50 m in the first 5 s. The car's acceleration is

4 M/S

Which of the following is not true of molecular motion in a gas?

D. There is a definite average direction of motion at a given temperature.

The average pressure of the atmosphere at sea level corresponds to which one or more of the following?

E. 101 kPa and 15 lb/in2 are both correct.

Ohm's law

Holds only for metals

Relative to the radio signals sent out by a spacecraft headed away from the earth, the signals that are received on the earth have

a lower frequency

Scientific theories

must be constantly reviewed to see whether they are in accord with new experimental observations

Polarization is similar to

n/a

The fossil fuel least polluting to burn is

natural gas

When a real object is the distance f from a converging lens,

no image

The physics of a heat engine cannot be used to understand the operation of a

nuclear reactor

Heat transfer by convection occurs

only in liquids and gases

Which one of the following effects does not occur in all types of wave?

polarization

astrology

Is nonsense

A current-carrying wire is in a magnetic field with the direction of the current perpendicular to that of the field.

The wire tends to move perpendicular to the field

Ball A is thrown horizontally and ball B is thrown upward.

They have the same downward acceleration

Two waves meet at a time when one has the instantaneous amplitude A and the other has the instantaneous amplitude B. Their combined amplitude at this time is

a+b

The electrons in an atom

are some distance away from the nucleus

The mass of a 2,200-lb elephant is

1,000 kg

The proportion of the world's electricity that comes from nuclear energy is about

1/6

A car starts from a speed of 10 m/s with an acceleration of 2 m/s 2. The time needed for the car to reach 30 m/s is

10 s

In 6 min a person running at 10 km/h covers a distance of

1000 m.

The current in a 20-ohm electric heater operated at 240 V is

12 A

A net horizontal force of 2000 N is applied to an 800-kg car at rest. The car's speed after 5 s will be

12.5 m/s

A snail travels 45 cm in 20 min. Its average speed is

135 cm/h

Two charges, one positive and the other negative, are initially 2 cm apart and are then pulled away from each other until they are 8 cm apart. The force between them is now smaller by a factor of

16

The specific heat of water is 4.2 kJ/kg°C. The heat needed to warm 8 kg of water from 20°C to 70°C is

1680 kJ

A person is 5 ft 8.0 in. tall. This is equivalent to

173 cm

In order to double the average energy of the molecules in a gas at 200 K, its temperature must be changed to

400 k

When its brakes are applied, a car moving at 10 m/s undergoes an acceleration of -1.2 m/s 2. How far does the car travel before it comes to a stop?

42 m

A 50-kg person weighs

490N

When a magnetized iron bar is strongly heated, its magnetic field

becomes weaker

Heat transfer in a vacuum

can take place only by radiation.

Eventually, if bioethanol remains in use, it will probably be made from

cellulose

A converging lens of focal length f produces a virtual image of a real object when the object is

closer than f from the len

To prevent it from tumbling in flight, a projectile such as a football is sent off spinning. The physical principle involved is

conservation of angular momentum

A kilowatt hour is a unit of

energy

In the United States, bioethanol from corn is added to gasoline for vehicle fuel because

government action favors its production and use

Stars and planets are round because

gravity forces them into this shape

Living things

have evolved throughout the earth's history.

A hole is drilled to the center of the earth and a ball is dropped into it. When the ball is at the earth's center, compared with their respective values at the earth's surface,

its mass is the same and its weight is 0.

A bullet is fired upward. As it rises,

its mass remains the same while its weight decreases

The volt is the unit of electric

potential difference

A refrigerator

removes heat from a region and carries it elsewhere.

A pure musical note causes a thin wooden panel nearby to vibrate with the same frequency. This is an example of

resonance

An object moving in a circle at constant speed is accelerated

toward the center of the circle

Direct electric current cannot be used to operate

transformers

The watt, the unit of power, is equal to the

voltampere

Relative to the electric force between two protons, the gravitational force between them is

weaker

A 1-kg mass has a KE of 1 J when its speed is

C. 1/4 m/s

Mars is about 1.5 times as far from the sun as the earth and its mass is about 0.1 times the earth's mass. Relative to the gravitational force the sun exerts on the earth, the force it exerts on Mars is about

0.044 as much

A crane exerts an upward force of 200 N on a 20-kg crate. The crate's upward acceleration is

0.2 m/s 2

A horse has a power output of 1 hp (746 W) when it is pulling a cart. If the cart covers 100 m in 30 s, the force the horse exerts on the cart is

0.22 kN

A 1-N weight has a PE relative to the ground of 1 J when it is at a height of

1 m

The pressure on 100 liters of helium is increased from 100 kPa to 400 kPa. The new volume of the helium is

25 liters

The primary coil of a transformer has 200 turns and its secondary coil has 40 turns. If the current in the secondary coil is 25 A, the current in the primary coil is

5a

Six kJ of work is used to lift an object to a height of 100 m. The object's approximate mass is

6 kg.

Average energy use per person in the United States today is about`

7.3 kW

An 800-kg car moving at 80 km/h collides head-on with a 1200-kg car moving at 40 km/h in the opposite direction. If they stick together, the wreckage now has an initial speed of

8 km/h

An electric iron draws a current of 15 A when connected to a 120-V power source. Its resistance is

8 ohms

What distinguishes the scientific method from other ways of looking at the natural world is

its reliance on experiment and observation

When heat is added to a body of matter, the resulting temperature increase does not depend upon

its shape

The first law of thermodynamics is the same as the

law of conservation of energy

You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be

less than 1.2 m deep.

If a spaceship 100 m long when at rest on the earth were to travel at nine-tenths the speed of light, its length as measured by an observer on the earth would be

less than 100 m

A molecule that has lost an electron becomes a

positive ion

Which of the following statements is true?

the moon is chiefly responsible for the tides, with the sun's influence modifying the tidal range.

Which of the following quantities is independent of the size and shape of an object composed of a given material?

density

A converging lens of focal length f produces a real image of a real object when the object is

farther than f from the lens

The stars in a constellation

form a pattern in the sky as seen from the earth

When the sun, the earth, and the moon are all in line,

high tides are higher than usual and low tides are lower than usual


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