physics final exam study guide
The muzzle velocity of a certain gun is 100 m/s. Neglecting air resistance, at the end of 1 s a bullet fired straight up into the air will have traveled a distance of about
(100 - 5) m.
On a chilly 10°C day, your friend who likes cold weather, wishes it were twice as cold. Taken literally, this temperature would be
-131.5°C.
A falling skydiver of mass 100 kg experiences 500-N air resistance. The acceleration of the skydiver is
0.5 g
Buoyant force is greatest on a submerged
1 cubic centimeter of lead and aluminum
A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both move with a combined momentum of
1 unit.
A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the ball when it is half way to the top of its path is about
10 N
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is
10 N
The gain in speed each second for a freely falling object is about
10 m/s
What is the weight of water displaced by a 100-ton floating ship?
100 tons
A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
16 times the KE.
If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficiency is
18%
Ignoring air drag, what is the maximum speed that can be given to a horizontally moving tennis ball as it clears the net 1.25 m high to remain within the edge of the court, which is 12.0 m distant?
24 m/s
Consider a piece of metal that is at 5°C. If it is heated until it has twice the thermal energy, its temperature will be
283°C.
If a baseball being thrown goes from zero to 30 m/s in 0.1 s, what is its average acceleration?
300 m/s/s
A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 s?
50 m/s
The scientist to first introduce the concept of inertia was
Galileo
If glass expanded more than mercury, then the column of mercury in a mercury thermometer would rise when the temperature
decreases
A popular swinging-balls apparatus consists of an aligned row of identical elastic balls that are suspended by strings so they barely touch each other. When two balls are lifted from one end and released, they strike the row and two balls pop out from the other end. If instead one ball popped out with twice the speed of the two, this would be a violation of conservation of
energy
The temperature at the bottom of Lake Tahoe, high in the Sierra Mountains in California, at this moment is
exactly 4°C.
Whereas Aristotle relied on logic in explaining nature, Galileo relied on
experiment
If the volume of an object were to double while its mass stays the same, its density would
halve
Which of the following expands most when the temperature is increased? Equal volumes of
helium
When a boat sails from fresh water to salt water, the boat will float
higher in the water.
If a nonrotating object has no acceleration, then we can say for certain that it is
in mechanical equilibrium.
If you are carrying a heavy bag of groceries and bang your hand against the wall, the concept that most explains why you are hurt is
inertia
Whenever the net force on an object is zero, its acceleration
is zero
According to the impulse momentum equation Ft = change in (mv), a bungee jumper in fall has momentum which is reduced by the force F exerted by the bungee cord. If m is the mass of the jumper, then v in the equation is the speed of the
jumper
When an iron ring is heated, the hole becomes
larger
From Earth, one satellite appears to overtake another. The faster satellite is
lower
A kilogram is a measure of an object's
mass.
Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed about Jupiter would be
more than 8 km/s.
A good reflector of radiation is a
poor absorber of radiation.
The period of a satellite, the time it takes for a complete revolution, depends on the satellite's
radial distance
A substance can absorb heat energy by the process of
radiation, convention, conduction
An inventor discovers a harmless and tasteless salt, which, when added to water changes its boiling point. The market value for this salt will be best if the salt
raises the boiling point of water.
A heavy rock and a light rock in free fall have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the
ratio of force to mass is the same.
A refrigerator
removes thermal energy from inside the refrigerator.
An egg is placed at the bottom of a bowl filled with water. Salt is slowly added to the water until the egg rises and floats. From this experiment, one concludes
the density of salt water exceeds the density of egg.
Evaporation is a cooling process because
the more energetic molecules are able to escape the liquid
Compared to the buoyant force of the atmosphere on a 1-L helium-filled balloon, the buoyant force of the atmosphere on a near by 1-L solid iron block is
the same
If an object radiates more energy than it absorbs, its
thermal energy and temperature decrease
Suspend a pair of Ping-Pong balls from two strings so there is a small space between them. If you blow air between the balls, they will swing
toward each other
Compared with a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much
volume, mass, inertia
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball that is initially at rest. The bowling ball and putty are then set in motion with a speed of
1/6 m/s.
A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is
10%
Two people, one twice as massive as the other, attempt a tug-of-war with 12 m of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of
4 m
Suppose a miracle car has a 100% efficient engine and burns fuel that has a 40 MJ/L energy content. If the air drag and overall frictional forces on this car traveling at highway speeds is 1000 N, what is the overall limit in distance per liter it could be driven on the highway?
40 km
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
Throw an object at an angle upward. With no gravity it will follow a straight-line path. But because of gravity, at the end of 1 s, it is
5 m below the straight line.
Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power does the elevator use?
50 W
A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?
6 N
An object is in free-fall. At one instant, it travels at a speed of 50 m/s. Exactly 1 s later, its speed is about
60 m/s.
A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?
80 J
While a car travels around a circular track at constant speed, its
NOT velocity is zero, acceleration is zero
A flower pot of mass m falls from rest to the ground below, a distance h. Which statement is correct?
The KE of the pot when it hits the ground is proportional to h.
The molecules in a room-temperature glass of water jostle around at
a great variety of speeds.
A math book and a physics book are tied together with a length of string. With the string taut, one book is pushed off the edge of a table. As it falls, the other book is dragged horizontally across the table surface. With no friction, acceleration of the books is
a value between zero and g.
Disregarding air resistance, objects fall at constant
acceleration
Inside a freely falling runaway elevator, your
apparent weight is zero.
Suppose an astronaut in outer space wishes to play a solitary "throw, bounce, and catch" game by tossing a ball against a very massive and perfectly elastic concrete wall. If the ball is as massive as the astronaut, the
astronaut will never catch the first bounce.
A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground
at the same time as the lighter object.
In the vacuum of outer space, there is no
atmospheric pressure
A supplier wants to make a profit by buying metal by weight at one altitude and selling it at the same price per pound at another altitude. The supplier should
buy at a high altitude and sell at a low altitud
When an object is partly or wholly immersed in a liquid, it is buoyed up
by a force equal to the weight of liquid displaced.
Consider a steaming aluminum soda-pop can that contains a small amount of boiling water. When it is quickly inverted into a bath of cooler water, the can is dramatically crushed by atmospheric pressure. This occurs because the pressure inside the can is rapidly reduced by
condensation of steam inside
If air were a better conductor than it is, at nighttime the Earth would be
considerably colder.
Compared to the buoyant force of the atmosphere on a 1-kg helium-filled balloon, the buoyant force of the atmosphere on a near by 1-kg solid iron block is
considerably less.
When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is
copper expands more than iron.
Compared with the force that brings a small car to a stop, the force required to bring a heavy truck traveling at the same speed to a stop
depends on the time involved.
A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is
doubled
A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor
exactly below the midpoint of the ceiling.
It is possible to wholly convert a given amount of heat energy into mechanical energy.
false
Energy transfer by convection is primarily restricted to
fluids
When you touch a cold piece of ice with your finger, energy flows
from your finger to the ice.
A large and a small person wish to parachute at equal terminal velocities. The larger person will have to
get a larger parachute.
According to Newton, the greater the masses of interacting objects, the
greater the gravitational force between them.
A clerk can lift containers a vertical distance of 1 m or can roll them up a 2-m-long ramp to the same elevation. With the ramp, the applied force required is about
half as much.
Which of the following contracts most when the temperature is slightly increased? Equal volumes of
ice water
A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun
if the mass of the bullet equals the mass of the gun.
Suppose you are standing on a weighing scale and all of a sudden the atmosphere vanished. The reading on the scale would
increase
Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will
increase
Ice has a lower density than water because ice
is made of open-structured, hexagonal crystals.
A pair of tennis balls fall through the air from a tall building. One ball is regular and the other is filled with lead pellets. Air resistance just before they hit is actually greater for the
lead-filled ball.
According to Newton, the greater the distance between masses of interacting objects, the
less the gravitational force between them.
An object that has potential energy may have this energy because of its
location
A heavy glass ball is placed in a pie pan that floats in a bucket. The water level at the side of the bucket is marked. Then the glass ball is removed and allowed to sink in the bucket. The water line at the side of the bucket is now
lower
What does an object have when moving that it doesn't have when at rest?
momentum
If an object has kinetic energy, then it also must have
momentum.
A ball is thrown vertically into the air. Because of air resistance, its time coming down compared to its time going up is
more
Alcohol is less dense than water. If alcohol is used to make a barometer on a day when atmospheric pressure is normal, the height of the alcohol column would be
more than 10.3
A lunar month is about 28 days. If the Moon were farther from Earth than it is now, the lunar month would be
more than 28 days.
Food cooked in boiling water in the mountains cooks slower than when cooked at sea level. If the temperature under the pot is increased, the food will cook
neither faster nor slower
Which requires the most amount of work on the brakes of a car?
slowing down from 100 km/h to 70 km/h.
The resistive force of friction occurs for
solids, liquids, gases
Which involves the larger number of calories?
the condensation of 1 g of steam at 100oC to 100oC water
The brakes are slammed on a speeding truck and it skids to a stop. If the truck were heavily loaded so it had twice the total mass, the skidding distance would be
the same
If you push a crate across a level floor at constant speed, the friction between the crate and the floor is
the same amount as your pushing force.
Neglecting friction, a large block of ice and a small block of ice start sliding down an incline together. The heavier block will get to the bottom
the same time as the light block.
The speeds of the planets about the Sun depend on
their distances from the Sun.
The fact that a thermometer "takes its own temperature" illustrates
thermal equilibrium