PSC1121 MIDTERM REVIEW
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
