Physical Science Test 2
The length of a certain wire is kept same while its radius is doubled. What is the change in the resistance of this wire?
(1/4) reduced by a factor of 4
A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 s later?
100 m
A projectile is launched vertically at 100 m/s. If air resistance can be neglected, at what speed does it return to its initial level?
100 m/s
A pair of 6-W and 100-W incandescent lamps are intended for 120-V operation. Which lamp draws more current?
100-W lamp
A power line with a resistance of 2 ohms draws a current of 80 A. The power dissipated in the line is
12,800 W
A certain bulb with a resistance of 95 ohms and labeled "150 W" is designated for use in a
120-V circuit
a nutritionist in the United States measures the food energy in units of
Calories
The length of a certain wire is doubled while its radius is kept constant. What is the change in the resistance of this wire?
it is doubled
the greatest expansion of water occurs when
it turns to ice
to say that an object is electrically polarized is to say
it's charges have been rearranged
if the sun were twice as massive
its pull on the Earth would double and earth's pull on the Sun would double
when we talk about electric power we're talking
joules per second and watts
Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that accelerated downward?
less compressed
heat is thermal energy that flows due to
temperature differences
The fact that a thermometer "takes its own temperature" illustrates
thermal equilibrium
the fact that a thermometer 'takes its own temperature' illustrates
thermal equillibrium
Two lamps, one with a thick filament and one with a thin filament, are connected in series to a battery. The voltage is greater across the lamp with the
thin filament
The motion of particles that contribute to temperature are
translational
the motion of molecules that most affects temperature is
translational motion
An Earth satellite is simply a projectile freely falling around Earth
true
At absolute zero, a substance has no more energy to give up.
true
The lowest temperature possible in nature is -273°C.
true
To say that something is twice as hot as another suggests the hotter thing has twice the thermal energy.
true
if the same quantity of heat is added to both a 1-liter and 2-liter container of water, the temperature change of water in the 1-liter container will be
twice
Consider two planets in space that gravitationally attract each other. If the mass of one planet is doubled, and the distance between them doesn't change, then the force between them is
twice as much
compared to the mass of a proton, the mass of an electron is
very much less
inside a freely falling elevator your
weight is zero
inside a freely-falling elevator your
weight is zero
If the Earth had twice its present radius and twice its present mass, what would happen to your weight?
weight would be half
strictly speaking, when you step off a curb you are momentarily
weightless
A metal ring with a gap in it is shaped like the letter C. When heated, the gap becomes
wider
The electric resistance of a superconductor is
zero
(
)
the lowest temperature possible in nature is
-273 C
the current in a 100-W bulb connected to a 120-V source is
.83 A
the temperature of melting ice is
0 C and 32 F
absolute zero corresponds to a temperature of
0 K and -273 C
A charge of 12. C passes through an electroplating apparatus in 2.0 min. What is the average current?
0.1 A
how much current is in a 60-W light bulb connected to 120 V?
0.5 A
A bullet fired horizontally hits the ground in 0.5 s. If it had been fired with twice the velocity it would have hit the ground in
0.5 sec
if a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the time it takes to reach the top of its path is
1 sec
the temperature of boiling water is
100 C and 212 F
a woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface. What is her weight there.
100 N
Find the ratio of the gravitational force between two planets if the masses of both planets are quadrupled but the distance between them stays the same.
16
two charges separated by 1 m exert a 1.0N force on each other. if the charges are pushed to .25-m separation, the force on each charge will be
16 N
What potential difference is required to cause 2.0 A to flow through a resistance of 8.0 Ω?
16 V
If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the total time to return to its starting position is
2 sec
When a battery does 24 J of work on 10 C of charge, the voltage it supplies is
2.4 V
the electric power of a lamp that carries 2 A at 120 V is
240 W
A length of wire has resistance R. The same wire twice as long has resistance
2R
The electric force on a 2 -C charge is 60 N. How great is the electric field at the charge location?
30 n/c
What would be the temperature of 50 g of 20°C water mixed with 80 g of 40°C water?
32.3 C
Consider a pair of planets for which the distance between them is decreased by a factor of 6. How many times does the force between them increase?
36
the power dissipated in a 4-ohm resistor carrying 3 A is
36 W
If the masses of two planets triples and the distance between reduces by half, the force between them would be
36 times as much
Two charges separated by 1 m exert a 1.0-N force on each other. if the magnitude of each charge is doubled, the force on each charge will be
4 N
A ball is thrown horizontally from the top of a tall cliff. Three seconds later, the ball has fallen a vertical distance of
45 m
A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of
5 m
increasing the temperature of 50 grams of water by 1 C requires
50 calories
A projectile is launched straight upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is
50 m/s
what is the force of gravity on a 500-N woman standing on Earth's surface?
500N
A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of
5m
a pair of 60-W and 100-W incandescent lamps are intended fro 120-V operation. which lamp has a greater resistance?
60 W lamp
A projectile is launched at an angle of 15° above the horizontal and lands downrange. With no air resistance, what other projection angle for the same speed would produce the same down range distance?
75 degrees
The temperature of water rises when 2.00 calories are added. It will rise the same when
8.38 J are added
What is the magnitude of the gravitational force between Earth and a 1-kg body at its surface?
9.8 N
what is the power rating of a device that draws 0.8 A when connected to 120 V?
96 W
Where do you weigh more: at sea level or on top of one of the peaks of the Rocky Mountains?
at sea level
in the vacuum of outer space, there is no
atmospheric pressure
if the Earth had twice its present radius and twice its present mass, what would happen to your weight?
be half
as entropy in a system increases, energy within the system
becomes less ordered
a very massive object A and a less massive object B move toward each other under the influence of gravity. which force, if either, is greater?
both forces are the same
A hunter fires a bullet from a horizontally-held rifle while simultaneously dropping another bullet from the side of the rifle. Which bullet hits the ground first?
both hit at the same time
heat energy is measured in units of
both joules and calories
To say that electric charge is conserved is to say that electric charge
can neither be created nor destroyed
the electric force between charges is strongest when the charges are
close together
The specific heat capacity of aluminum is more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the wire to heat up quickest will be
copper
When the distance between two stars doubles, the force between them
decreaes by one-quarter
A rock is thrown upward at 50° with respect to the horizontal. As it rises, its vertical component of velocity
decrease
if Earth's mass decreased to one-half its original mass with no change in radius, your weight would
decrease to one-half
if your mass remained the same while the mass of Earth doubled while staying the smae size, your weight would
double
an object is placed exactly halfway between the Earth and the Moon. the object will fall toward the
earth
every proton in the universe is surrounded by its own
electric field and gravitational field
a positive ion has a deficiency of
electrons
consider two planets in space that gravitationally attract each other. if the masses of both planets are double, and the distance between them doesn't change, then the force between them is
four times as much
when you touch a hot penny in sunlight with your finger, energy flows
from the penny to your finger
When you touch a piece of ice with your finger, energy flows
from your finger to the ice
when you touch a piece of ice with your finger, energy flows
from your finger to the ice
according to Newton, the greater the masses of interacting objects, the
greater the gravitational force
A baseball is tossed at a steep angle into the air and makes a smooth parabolic path. Its time in the air is t, and it reaches a maximum height h. Assume that air resistance is negligible. find the height reached by the ball (in terms of t)
h=(gt^2)/8
if the radius of the Earth somehow decreased with no change in mass, your weight would
increase
if the mass of Earth somehow increased with no change in radius, your weight would
increase also
If you heat a copper wire its electric resistance
increases
two object move toward each other due to gravity. as the objects get closer and closer, the force between them
increases
two objects move toward each other due to gravity. as the objects get closer and closer, the acceleration of each
increases
when the distance between two stars decreases by half, the force between them
increases four times as much
whether one object is warmer than another has most to do with
molecular kinetic energy
Whether one object is warmer than another object has most to do with
molecular kintetic energy
Would the springs inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that accelerated upward?
more compressed
Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will draw
more current
at some point between Earth and the Moon, the forces due to gravity on a space traveler would be the same. this point is
nearer the moon
The amount of gravitational force that acts on a space vehicle that orbits Earth is
nearly as much as the vehicle's weight on Earth's surface
As you comb your hair, electrons are rubbed onto the comb, which becomes
negatively charged
A projectile is fired horizontally. With no air resistance it maintains its horizontal component of velocity because
no horizontal forces act on it
at absolute zero, a substance has
no more energy to give up
if the masses of two planets doubles and the distance between them also doubles, the force between them would be
none of the above
which is the smallest unit of measurement for temperature
one Farenheit degree
Electric field lines about a point charge extend
outward when the charge is positive
If you strip electrons from an atom, the atom becomes a
positive ion
the nucleus of an atom is charged
positively
when you remove electrons from a metal cup, the cup becomes
positivley charged
When the distance between two charges is halved, the electric force between the charges
quadruples
when the distance between two charges is halved, the electric force between the charges
quadruples
roll a bowling ball off the edge of a table. as it falls, its horizontal component of motion
remains constant
A pair of positively-charged plastic straws tend to
repel each other
one main difference between gravitational and electric forces in that electric forces
repel or attract
