physical science test 2
The lowest temperature possible in nature is
-273°C
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 s.
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 weigh there?
100 N
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 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?
500 N
What is the magnitude of gravitational force between two 1−kg−kg bodies that are 1 m apart?
6.67 x 10^(-11) N
If 100 joules of heat is added to a system that does 40 joules of external work, by how much is the thermal energy of the system raised?
60 J
The period of the second hand on a clock is
60 seconds
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° (90-15=75)
An Earth satellite is simply a projectile freely falling around the Earth.
True
The lowest temperature possible in nature is -273°C.
True
The vibrations of a longitudinal wave move in a direction
along the direction of wave travel
In the vacuum of outer space, there is no
atmospheric pressure
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
Absolute zero corresponds to a temperature of
both- 0 K and -273 C
The temperature of boiling water is
both- 100 degrees C or 212 degrees F
The temperature of melting ice is
both- 32°F and 0°C
If the mass of Earth somehow increased with no change in radius, your weight would
increase also.
Two objects move toward each other due to gravity. As the objects get closer and closer, the force between them
increases
When disorder in a system increases, does entropy increase or decrease?
increases
If the Earth had twice its present radius and twice its present mass, what would happen to your weight? Explain.
it would be split in half
A sound wave is a
longitudinal wave
Whether one object is warmer than another object has most to do with
molecular kinetic energy
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
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
During a single period, the distance traveled by a wave is
one wavelength
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
Roll a bowling ball off the edge of a table. As it falls, its horizontal component of motion
remains constant.
A baseball is tossed at a steep angle into the air and makes a smooth parabolic path. Its time in the air is tt, and it reaches a maximum height hh. Assume that air resistance is negligible. (1) Find the height reached by the ball. (2) If the ball is in the air for 3.0 s, find a height it reaches. (3) If the ball reached the same height as when tossed at some other angle, would the time of flight be the same?
(1) h= gt^2 / (8) (2) h= 11 m (3) yes
(1) Which warms faster when heat is applied: iron or silver? (2) Which has the higher specific heat capacity?
(1) silver (2) iron
The explanation for all types of refraction involves a change in
speed.
Heat is thermal energy that flows due to
temperature differences
On days when the air nearest the ground is colder than air above, sound waves
tend to be refracted downward
The speed of a sound wave in air depends on
the air temperature
When a 1-kg metal pan containing 1 kg of cold water is removed from the refrigerator onto a table, which absorbs more heat from the room: the pan or the water?
the water
The fact that a thermometer "takes its own temperature" illustrates
thermal equilibrium
Which has the higher specific heat capacity, water or land?
water
Inside a freely-falling elevator you would have no
weight
Inside a freely-falling elevator your
weight is zero
Strictly speaking, when you step off a curb you are momentarily
weightless.
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
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 s
Which law of thermodynamics tells us what is most probable in nature?
2nd law
If the masses of two planets triples and the distance between reduces by half, the force between them would be
36 times as much
If Earth's mass decreased to one-half its original mass with no change in radius, your weight would
decrease to one-half.
Which of these involves the most thermal energy: 1 calorie, 1 Calorie, or 1 joule?
1 Calorie
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 s
A projectile is launched vertically at 100 m/sm/s. If air resistance can be neglected, at what speed does it return to its initial level?
100 m⋅s^−1
At what temperature do the combined effects of contraction and expansion produce the smallest volume of water?
4 degrees C
How many joules are needed to change the temperature of 1 g of water by 1 degree C?
4.19 J
How much heat is needed to change 200 g of water at 80C to steam at 100c
4000 calories (Q= m x c x change in T = 200 g x 1 cal/ g degree C x (100-80) = cancel the gs = 200(20)= 4000 calories)
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 (h= (1/2)gt^2 , h= (1/2) x 10 x (3^3) = 45)
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
A wave travels an average distance of 5 m in 1 s. What is the wave's velocity?
5 m/s
The temperature of water rises when 2.00 calories are added. It will rise the same when
8.38 J are added
Consider a pair of planets for which the distance between them is decreased by a factor of 3. How many times does the force between them increase?
9
An object is placed exactly halfway between the Earth and the Moon. The object will fall toward the
Earth.
At absolute zero, a substance has no more energy to give up.
True
To say that something is twice as hot as another suggests the hotter thing has twice the thermal energy.
True
If the sun were twice as massive
both (Earth's pull on the Sun would double, its pull on the Earth would double)
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
To say that electric charge is conserved is to say that electric charge
can neither be created nor destroyed
When the distance between two stars doubles, the force between them
decreases by one-quarter
A rock is thrown upward at 50° with respect to the horizontal. As it rises, its vertical component of velocity
decreases.
If your mass remained the same while the mass of Earth doubled while staying the same size, your weight would
double.
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them doesn't change, then the force between them is
four times as much.
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 between them.
If the radius of the Earth somehow decreased with no change in mass, your weight would
increase.
While at a concert, a wind blows directly from the orchestra toward you. The wavelength of the sound you hear is
increased
When the distance between two stars decreases by half, the force between them
increases to four times as much.
Two objects move toward each other due to gravity. As the objects get closer and closer, the acceleration of each
increases.
If you double the frequency of a vibrating object, its period
is half
The greatest expansion of water occurs when
it turns to ice
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
Why doesn't the Moon fall toward Earth like apples do?
moon does fall but due to its tangential motion it also falls around Earth
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
If the masses of two planets doubles and the distance between them also doubles, the force between them would be
none of the above (one-quarter, half as much, twice as much, four times as much.)
When the distance between two charges is halved, the electric force between the charges
quadruples
A pair of positively-charged plastic straws tend to
repel each other
Does a hot object contain thermal energy, or does it contain heat?
thermal energy
The motion of particles that contribute to temperature are
translational.
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
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