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169 terms

Physics Final Review

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An object in equilibrium is an object
Moving with constant velocity.
When you stand at rest on a pair of bathroom scales, the readings on the scales will always
Add up to equal your weight.
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant
10 N.
A truck is moving at a 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.
If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is
Inertia.
A horse gallops a distance of 10 kilometers in a time of 30 minutes. Its average speed is
20 km/h
A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is
Zero.
While an object near the Earth's surface is in free fall, its
Acceleration increases.
A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is
Zero.
Twelve seconds after starting from rest, an object falling freely will have a speed of
More than 100 m/s.
If an object moves with constant acceleration, its velocity must
Change by the same amount each second.
If a car increases its velocity from zero to 60 km/h in 10 seconds, its acceleration is
6 km/h/s
It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?
About 60 m.
If a car accelerates from rest at 2 meters per second, its speed 3 seconds later will be about
4 m/s.
At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed should be about
60 m/s.
Disregarding air resistance, objects fall with constant
Acceleration
If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about
1 second.
Your weight is
The gravitational attraction force between you and the Earth.
If one object has twice as much mass as another object, it also has twice as much
Inertia.
Compared to the mass of a certain object on Earth, the mass of the same object on the moon is
The same.
The newton is a unit of
Force.
A force is a vector quantity because it has both
Magnitude and direction.
An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is
5 N.
The force of friction on a sliding object is 10 Newtons. The applied force needed to maintain a constant velocity is
10 N.
Whenever the net force on an object is zero, its acceleration
Is zero.
A girl pills on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration in meters per second per second?
3
A bag of groceries has a mass of 10 kilograms and a weight of
10 N.
A 10 kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block in meters per second per second is?
10
Two factors that greatly affect air resistance on falling objects are the
Size and mass of the object.
When a falling object has reached its terminal velocity, its acceleration is
Constant.
Two objects of the same size but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the
Both hit at the same time.
A sack of potatoes weighing 200 N falls from an airplane. As the velocity of fall increase, air resistance also increases. When air resistance equals 200 N, the sack's acceleration in meters per second per second is?
Zero
A skydiver steps from a helicopter and falls for a few seconds until he reaches his terminal velocity. Thereafter, until he opens his parachute, his acceleration
Is zero.
A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the
None of these.
A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is
1000 N.
A person is attracted toward the center of Earth by a 500 N gravitational force. The Earth is attracted toward the person with a force of
500 N.
Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by
Both the same
A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the diver down. What is the reaction to this form?
None of these
A bird sitting on the limb of a tree is moving about 30 km/s with respect to the Sun. If the bird takes 1 second to drop down to a worm below, the worm would be 30 km downrange from the bird when it reached the ground. This faulty reasoning is best countered with Newton's
1st law.
The force exerted on the tires of a car to directly accelerate it along a road is exerted by the
Road.
Which of the following has the largest momentum relative to the Earth's surface?
A pick up truck speeding across the highway.
It is correct to say that impulse is equal to
The change in momentum it produces.
A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the
Rifle has much more mass than the bullet.
Two objects have the same size ad shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater
None of these
When you are in the way of a fast-moving object and cant get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a
Long time.
A large metal ball is shot from a cannon with a short ball were to be shot from cannon with a longer barrel, its muzzle velocity would be
The same
A 4 kg ball has a momentum of 12 kg m/s. What is the balls speed?
48 m/s.
A 1000 kg car moving at 10 m/s brakes to a stop in 5s. The average braking force is
5000 N.
If you push for a half hour of a whole hour against a stationary wall
No work on the wall is done in either case.
If you push an object twice as far while applying the same force, you do
Twice as much as work.
A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of
Power.
Do 100 J of work in 50 s and your power output is
2 W.
An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is
The same.
An object that has kinetic energy must be
Moving.
A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter long ramp to the same elevation. With the ramp, the applied force required is about
The same.
A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy that is
40 J.
The ball rolling down an incline has its maximum potential energy at
The top.
A ball rolling down an incline has its maximum kinetic energy at
The bottom.
What task requires the most work; lifting a 50 kg sack 2 meters of lifting a 25 kg sack of 4 meters?
Both require the same amount of work.
A TV ser is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?
40 J.
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.
A car moves 4 times as fast as another identical. Compared to the slower car, the faster car has
16 times the kinetic energy
Strictly speaking more fuel is consumed by your car if an air conditioner, headlights, or even a radio is turned on. This statement is
True.
A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is
10%
A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of
5000 J.
Which moves faster in m/s on a merry go round: a horse on the inside or a horse on the outside near the outer rail?
Outside horse.
A broom is easier to balance upright when heavier end (the brush end) is
Nearest your hand.
A coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be
The coin.
The rotational inertia of your leg is greater when your leg is
Bent.
On a balanced see-saw, a boy three times as heavy as his partner sits
1/3 the distance from the fulcrum.
Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll multiply the torque by
Two.
The long, heavy, tail of a monkey enables the monkey to easily vary its
Center of gravity.
The center of mass of a human body is located at a point
That changes as a person bends over.
The famous Leaning Tower of Pisa doesnt topple over because its center of gravity is
In the same place of its center of mass.
When a twirling ice skater brings her arms inward, her rotational speed
Remains the same.
Two people are balanced on a seesaw, If one person leans forward the center of the seesaw, that person's end of the seesaw will
Rise and then fall.
A car travels in a circle with constant speed. The net force on the car is
Directed toward the center of the curve.
If you balance a broom horizontally on one finger, the center of gravity of the broom will be above your finger-closer to the bristles end than the handle end. If you saw the broom in two pieces at that point and weigh the two parts on a scale, you'll find that the heavier part is the
Bristles part
According to Newton, the greater the masses of interacting objects, the
Greater the gravitational force between them.
According to Newton, doubling the distance between two interacting objects
Divides by 4 the gravitational force between them.
If the mass of the Earth somehow increased with no charge in radius, your weight would
Increase also.
Inside a freely falling elevator, there would be no
Apparent weight for you.
An asteroid exerts a 360 N gravitational force on a nearby spacecraft. This force is directed
Toward the asteroid.
If your mass, the mass of the Earth, and the mass of everything in the solar system were twice as mush as it is now, yet everything stayed the same size, your weight on Earth would
Quadruple.
If the radius of the Earth somehow decreased with no change in mass, your weight would
Increase.
An object is placed exactly halfway between the Earth and Moon. The object will fall toward the
Earth.
A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above the Earth's surface. How much would she weigh there?
100 N.
A very massive object A and a less massive object B move toward each other under the influence of gravitation. Which force, if either, is greater?
The force on A.
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
Remain constant.
Passengers in a high-flying jumbo jet feel their normal weight in flight, while passengers in the orbiting space shuttle do not. This is because passengers in the space shuttle are
Without support forces.
How far must one travel to get away from the Earth's gravitational field?
Forget it; you cant travel for enough.
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity
Decreases.
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity
Remains unchanged
A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is
5 m.
Roll a bowling ball off the edge of a table. As it falls, its horizontal component of velocity
Remains constant.
A bullet fired horizontally from a rifle begins to fall
As soon as it leaves the barrel.
An Earth satellite is simply a projectile
Freely falling around the Earth.
Earth satellites are typically more than 100 km high so as to be above the Earth's
Atmosphere.
A projectile is fired into the air at an angle of 50 degrees with the ground and lands on a target that is a the same level at which the projectile started. It will also land on the target if it is fired at one angle of
40 degrees.
What prevents satellites such as the space shuttle from falling?
Nothing, they are continually falling as they orbit the Earth.
The circular path of a satellite is an elliptical orbit. The satellite travels fastest when it is
Nearest the Earth.
A satellite near the Earth makes a full circle in about an hour and a half. How long would a satellite located as far away as the moon take to orbit the Earth?
About 28 days.
Communications and weather satellites always appear at the same place in the sky. This is because these satellites are
Orbiting the Earth with a 24-hour period.
Compared to the period of satellites in orbit close to the Earth, the period of satellites in orbit far from the Earth is
Longer.
When a chocolate bar is cut in half, its density is
unchanged.
If a loaf of bread is compressed, its
density decreases.
If the mass of an object were to double while its volume remains the same, its density would
Double.
Compared to the density of a kilogram of feathers, the density would
more
When weight is applied to the top of a stone arch, all of the stone blocks in the arch undergo
Compression.
When a load is placed in the middle of a horizontal beam supported at each end, the bottom part of the beam undergoes
Tension.
You wish to bolt a sign to a horizontal 1-beam supporting a bridge. You will weaken the beam least if you drill the bolt-holes through the
more.
Compressed to the volume of a kilogram of feathers, the volume of a kilogram of lead is
Less.
Stone slabs are stronger under
Compression
The strength of a rope depends on its
Thickness.
An iron block is placed in a furnace where is heated and consequently expands. In the expanded condition, its density
Is less.
Which potatoes when peeled produce the most peelings?
10 kg of small potatoes.
Which has more skin, and elephant or mouse?
Elephant
Which has more skin compared to its body weight, an elephant or a mouse?
A mouse
Doubling the linear size of an object multiplies its area by
4 and its volume by 8
When a living cell doubles in diameter, the amount of its material to be nourished is multiplied by eight, but the amount of membrane through which to feed it is multiplied by
4
Which cooks faster in boiling oil?
A sliced potato.
A dome-shaped house is more heat efficient than a rectangular house because the dome has
Less area compared to its volume
If an elephant grew to twice its height, the area of its ears would be about
Four times what it was
If an elephant grows to twice its normal height, its weight will be multiplied by about
8
In cold weather, your hands will be warmer if you wear
Mittens
In cooking a turkey in a conventional oven at a given temperature, compared to a medium sized turkey, a large turkey takes
More time per pound to cook.
If each dimension of a steel bridge is scaled up ten times, its strength will be multiplied by about
Ten, and its weight by ten also.
The pressure in a liquid depends on liquid
Density
Pumice is a volcanic rock that floats. Its density is
Less than the density of the water.
The reason that buoyant forces act upward on a submerged object is that
Upward pressure against the bottom is greater than downward pressure against the top of the submerged object.
A fish normally displaces its own
Both of these
Compared to the density of water, the density of a fish is
The same.
What is the buoyant force acting on a 10 ton ship floating in the ocean?
10 tons
What is the weight of water displaced by a 100 ton floating ship?
100 tons
Blood pressure is normally greater in your
Feet
When holes are drilled through the wall of a water tower, water will spurt out the greatest horizontal distance from the hole closest to the
Bottom of the tower.
Lobsters live on the bottom of the ocean. The density of a lobster is
Greater than the density of sea water.
A lobster crawls onto a bathroom scale submerged at the bottom of the ocean. Compared to its weight above the surface, the lobster will have an apparent weight under water that is
Less.
A rock suspended by a string weighs 5 N out of water and 3 N when submerged. What is the buoyant force on the rock?
2 N.
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 the egg.
A block of Styrofoam floats on water while a same size block of lead lies submerged in the water. The buoyant force is greatest on the
Lead.
Buoyant force is greater on a submerged
1 kg block of lead.
Buoyant force is greatest on a submerged
The same as both.
When you float in fresh water, the buoyant force that acts on you is equal to your weight. When you float higher in the high-density water of the Dead Sea, the buoyant force that acts on you is
Equal to your weight.
When a boat sails from fresh water to salt water, the boat will float
Higher in the water
There is a legend of a Dutch boy who bravely held back the Atlantic Ocean by plugging a leak near the top of a dike with finger until help arrived. Which of the following is most likely?
The force on his finger would have been small enough for this to occur
The energy source responsible for the motion of molecules that make up the atmosphere is
Solar power
Atmospheric molecules do not fly off into outer space because
Earth gravitation
Atmospheric pressure is caused by the
Weight of the atmosphere
As a helium-filled balloon rises in the air it becomes
Bigger
The faster a fluid moves, the
Less its internal pressure
A suction cup sticks to a wall, it is
Pulled to the wall by the vacuum
Consider two mercury barometers, one with twice the cross-sectional area of the other. Neglecting capiliarily, mercury in the smaller tube will rise
The same height as the larger tube.
A helium filled balloon released in the atmosphere will rise rise until
The balloon and surrounding air have equal densities
As a woman hold her breath swims deeper and deeper beneath the water's surface, her density
Increases
When gas in a container is squeezed to half its volume and the temperature remains the same, the gas pressure
Doubles
An umbrella tends to move upwards on a windy day principally because
Air gets trapped under the umbrella, warms, and rises
Suspend a pari 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
Apart from each other
When you touch a cold piece of ice, energy flows
Both ways actually
Heat energy travels from an object with a high
Internal energy to an object with a high lower internal energy.
A substance that heats up a relatively quickly has a
HIgh specific heat
Before ice can form on a lake, all the water in the lake must be cooled to
Zero degrees C
Ice tends to form first
Surface of bodies water
When a iron ring is heater, the hole becomes
Either smaller or bigger, depending the ring thickness
When a bimetallic bar made of copper and iron strips is heated the bar bends toward the iron strip. The reason for this is
Iron gets hotter before copper
When water at 4 degrees C is heated, it expands. When water at 4 degrees C is cooled, it
Neither contracts or explains
During a very cold winter, water pipes sometimes burst. The reason for this is
Water!!
Aluminum has a specific heat capacity more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be
Both the same!!
The white hot sparks that strike your skin from a 4th of July type sparkler dont harm you because
They have a low temperature.