# Physics Chapter 4 Test 1

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question
Whenever a net force acts on an object, there is a change in the object's _______. a.shape. b.velocity. c.speed d.direction
b.velocity.
question
As you increase your push on a stationary crate, will friction on the crate increase also? a.The friction force increases and is in the same direction as your push. b.The friction force remains zero. c.The friction force increases and is opposite in direction to your push. d.The friction force decreases and is in the opposite direction as your push.
c.The friction force increases and is opposite in direction to your push.
question
When you push horizontally on a crate that doesn't slide on a level floor, how great is the force of friction on the crate? a.The friction force is zero. b.The friction force is equal to the mass of the crate times its acceleration. c.The friction force is equal to and in the same direction as your push. d.The friction force is equal and opposite to your push.
d.The friction force is equal and opposite to your push.
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Once the crate is sliding, how hard do you push to keep it moving at constant velocity? a.You push with a force slightly greater than the static friction force. b.You no longer need to push once the crate is sliding. c.You push with a force equal to and opposite the dynamic friction force. d.You push with a force slightly greater than the dynamic friction force.
c.You push with a force equal to and opposite the dynamic friction force.
question
Which varies with location, mass or weight? a.Both mass and weight vary with location. b.Weight varies with location, but mass does not. c.Mass varies with location, but weight does not. d.Both mass and weight are independent of location.
b.Weight varies with location, but mass does not
question
Shake something to and fro and you're measuring its what? Lift it against gravity and you're measuring its what? a.Shaking measures weight, whereas lifting measures mass. b.Shaking and lifting both measure weight. c.Shaking measures mass, whereas lifting measures weight. d.Shaking measures neither mass nor weight. Lifting measures weight.
c.Shaking measures mass, whereas lifting measures weight.
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What is the weight of a 1-kilogram brick resting on a table? a.10 N b.0.1 N c.1 N d.10 kg
a.10 N
question
How does acceleration depend on mass? a.Acceleration is inversely proportional to mass. b.Acceleration is constant at 9.8 m/s2. c.Acceleration is proportional to mass. d.Acceleration is independent of mass.
a.Acceleration is inversely proportional to mass.
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The unit of mass is the kilogram, and the unit of weight is the _______. a.Newton b.kilogram also. c.m/s^2 d.metric mass
a.Newton
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If the mass of a sliding block is tripled while a constant net force is applied, by how much does the acceleration change? a.The acceleration remains the same. b.The acceleration is reduced to 1/3 of its original value. c.The acceleration triples. d.The acceleration is zero.
b.The acceleration is reduced to 1/3 of its original value.
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How does the direction of acceleration compare with the direction of the net force that produces it? a.The acceleration is zero. b.The acceleration is opposite the direction of the net force. c.The acceleration is at right angles to the net force. d.The acceleration is in the direction of the net force.
d.The acceleration is in the direction of the net force.
question
State Newton's second law of motion. a.Acceleration is proportional to net force and mass. b.Acceleration is proportional to net force and inversely proportional to mass. c.Acceleration is constant at 9.8 m/s2. d.Acceleration is inversely proportional to net force and proportional to mass.
b.Acceleration is proportional to net force and inversely proportional to mass.
question
Use the "Force applied" slider to set the force applied on the elephant to somewhere in the middle of the range. After you have set the "Force applied" slider, do not change it again for this question. How would the acceleration change if the mass of the elephant were increased? a.It stays the same. b.It increases. c.It decreases.
c.It decreases.
question
Use the "Mass of elephant" slider to set the mass of the elephant to somewhere in the middle of the range. After you have set the "Mass of elephant" slider, do not change it again for this question. How would the acceleration change if the applied force on the elephant were increased? a.It decreases. b.It stays the same. c.It increases.
c.It increases.
question
Consider the video tutorial you just watched. Suppose that we duplicate this experimental setup in an elevator. What will the spring scale read if the elevator is moving upward at constant speed? a.Less than 18 N but greater than 0 N b.18 N c.0 N d.More than 18 N
b.18 N
question
What is the net force that acts on a 10-N falling object when it encounters 4 N of air resistance? When it encounters10 N of air resistance? a.The net forces are 14 N and 20 N, respectively. b.The net forces are 6 N and 0 N, respectively. c.The net forces are 6 N and 10 N, respectively. d.The net forces are 4 N and 0 N, respectivel
b.The net forces are 6 N and 0 N, respectively.
question
What two principal factors affect the force of air resistance on a falling object? a.The force depends mostly on mass and speed. b.The force depends mostly on mass and frontal area. c.The force depends mostly on g and mass. d.The force depends mostly on frontal area and speed.
d.The force depends mostly on frontal area and speed.
question
What is the acceleration of a falling object that has reached its terminal velocity? a.The acceleration is 0. b.The acceleration is -g. c.The acceleration is g2. d.The acceleration is g.
a.The acceleration is 0.
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Why does a heavy parachutist fall faster than a lighter parachutist who wears a parachute of the same size? a.Gravity is greater on the heavier person, so they fall at g. b.Terminal speed must be lower to make air drag equal the gravity force for a heavier person. c.Terminal speed must be higher to make air drag equal the gravity force for a heavier person. d.Terminal speed is inversely proportional to the mass of the parachutist.
c.Terminal speed must be higher to make air drag equal the gravity force for a heavier person.
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If two objects of the same size move through the air at different speeds, which encounters the greater air resistance? a.Both encounter the same air resistance. b.The faster object encounters more air resistance. c.The one at terminal velocity encounters less air resistance. d.The slower object encounters more air resistance.
b.The faster object encounters more air resistance.
question
A 1-kg stone and a 10-kg stone have the same acceleration in free fall because _______. a.the force of gravity is the same on each. b.air resistance has no effect c.the ratio of weight to mass is the same for each. d.they both fall equally.
c.the ratio of weight to mass is the same for each.
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As a skydiver gains speed in falling through the air, air resistance _______. a.becomes negligible when terminal speed is reached. b.decreases. c.cancels weight. d.increases.
d.increases.
question
Air resistance on a parachutist at terminal speed _______. a.no longer depends on speed b.is less for a heavy person c.is greater for a heavier person d.is the same for both a heavy and light person with the same size parachutes.
c.is greater for a heavier person
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Since an object weighs less on the surface of the Moon than on Earth's surface, does it have less inertia on the Moon's surface? a.No. b.Yes.
a.No.
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What is the net force acting on a 1-kg ball in free fall? Express your answer with the appropriate units.
10.0 N
question
A grocery bag can withstand 300 N of force before it rips apart. How many kilograms of apples can it safely hold? Express your answer with the appropriate units.
30.0 kg
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Free fall is motion in which gravity is the only force acting. Is a skydiver who has reached terminal speed in free fall? a.Yes. b.No.
b.No.
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Is a satellite above the atmosphere that circles Earth in free fall? a.No. b.Yes.
b.Yes
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Calculate the weight in newtons of a person having a mass of 60kg . Express your answer to two significant figures and include the appropriate units. Weight = mg
W = 600 N
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Susie Small finds that she weighs 350N . Calculate her mass. Express your answer to two significant figures and include the appropriate units. Weight = mg
m = 35 kg
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Calculate the acceleration of a 290000-kg jumbo jet just before takeoff when the thrust on the aircraft is 120000N . Express your answer to two significant figures and include the appropriate units. a=Fnet/m
a = 0.41 m/s^2
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A 1-kg mass at the Earth's surface weighs a.12 N. b.1 N. c.5 N. d.10 N. e.none of the above
d.10 N.
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The mass of a pet turtle that weighs 10 N is about a.1000 kg. b.10 kg. c.100 kg. d.1 kg. e.none of the above
d.1 kg.
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Compared to the mass of an apple on Earth, the mass of the apple on the Moon is a.zero. b.one sixth as much. c.six times as much. d.the same.
d.the same.
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An apple at rest weighs 1 N. The net force on the apple when it is in free fall is a.1 N. b.0 N. c.9.8 N. d.0.1 N. e.none of the above
a.1 N.
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An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is a.0.1 N. b.0 N. c.9.8 N. d.1 N. e.none of the above
b.0 N.
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A car has a mass of 1000 kg and accelerates at 2 m/s2. What net force is exerted on the car? a.1000 N b.500 N c.2000 N d.1500 N e.none of these
c.2000 N
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An object released from rest on another planet requires one second to fall a distance of 6 meters. What is the acceleration due to gravity on this planet? a.6 m/s2 b.15 m/s2 c.3 m/s2 d.12 m/s2 e.none of the above
d.12 m/s2
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A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time? a.200 m b.100 m c.300 m d.400 m e.none of the above
c.300 m
question
A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was a.1.2 m/s. b.30 m/s. c.15 m/s. d.45 m/s. e.none of the above
b.30 m/s.
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An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, the rock has a weight of a.4 N. b.3 N. c.2 N. d.5 N. e.1 N.
d.5 N.
question
A ball is thrown vertically into the air. Because of air resistance, its speed when it returns to its starting level compared with its initial speed is a.the same. b.more. c.less.
c.less.
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Suzie Skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration a.decreases. b.increases. c.remains unchanged regardless of air resistance.
a.decreases.
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A feather and a coin will have equal accelerations when falling in a vacuum because a.the ratio of both the feather's and coin's weight to mass is the same. b.their velocities are the same. c.the force of gravity is the same for each in a vacuum. d.the force of gravity does not act in a vacuum. e.none of the above
a.the ratio of both the feather's and coin's weight to mass is the same.
question
Recall Galileo's Leaning Tower experiment. With negligible air resistance, a heavy and a light object fall a.with the same increases in speed. b.with equal accelerations. c.to the ground in equal times. d.all of the above
d.all of the above
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A skydiver's terminal velocity will be greatest if she falls a.lying flat on her stomach. b.head first. c.lying flat on her back. d.with her parachute open.
question
The direction of the force of friction on a sliding crate is _______. a.usually at right angles to the force that produces sliding. b.opposite to the direction of sliding c.non-directional d.in the same direction as the force that produces sliding.
b.opposite to the direction of sliding
question
A crate sits at rest on a factory floor. Friction between the crate and floor occurs _______. a.only if the crate is pushed vertically as well as horizontally b.only if the crate is sliding. c.even when no pushing occurs. d.when the crate is pushed horizontally, whether sliding or not.
d.when the crate is pushed horizontally, whether sliding or not.
question
What is the condition for an object experiencing free fall? a.When gravity is the only force acting on an object, it is in free fall. b.When the net force on an object is zero, it is in free fall. c.When the net force on an object is equal and opposite to the gravity force, the object is in free fall. d.When there are no horizontal forces on an object, it is in free fall
a.When gravity is the only force acting on an object, it is in free fall.
question
Why doesn't a heavy object accelerate more than a light object when both are freely falling? a.The ratio of the weight to mass is the same for all objects in the same locality. b.The inertia of the heavy object is just enough smaller than the inertia of the lighter object to counteract the larger gravity force. c.The inertia of the heavy object equals the inertia of the lighter object, so their accelerations are the same. d.The larger air resistance force on the larger object makes it fall with the same acceleration.
a.The ratio of the weight to mass is the same for all objects in the same locality.
question
Whenever the net force on an object is zero, its acceleration a.is zero. b.may be more than zero. c.may be less than zero.
a.is zero.
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If an apple experiences a constant net force, it will have a constant a.acceleration. b.position. c.velocity. d.speed. e.more than one of the above
a.acceleration.
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If you double the net force on an object, you'll double its a.speed. b.acceleration. c.velocity. d.all the above
b.acceleration.
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If the net force on a cart is tripled, the cart's acceleration a.is more than three times as much. b.is two thirds. c.is one third. d.is three times as much.
d.is three times as much.
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A mobile phone is pulled northward by a force of 10 N and at the same time pulled southward by another force of 15 N. The resultant force on the phone is a.0 N. b.150 N. c.5N d.25 N.
c.5N
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The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is a.10 N. b.more than 10 N. c.less than 10 N.
a.10 N.
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A 10-N falling object encounters 10 N of air resistance. The net force on the object is a.6 N. b.0 N. c.4 N. d.10 N. e.none of these
b.0 N.
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An object's weight is properly expressed in units of a.cubic centimeters. b.meters. c.newtons. d.kilograms.
c.newtons.
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A kilogram is a measure of an object's a.mass. b.force. c.both of these d.neither of these
a.mass.
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Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much a.inertia. b.volume. c.mass. d.all of the above e.none of the above
d.all of the above
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Your weight as measured on your bathroom scale is a.equal to your mass. b.the force due to gravity on you. c.a property of mechanical equilibrium. d.all of the above
b.the force due to gravity on you.
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An object with twice as much mass as another object has twice as much a.inertia. b.speed. c.acceleration due to gravity. d.all of the above
a.inertia.
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In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the a.planet Jupiter. b.Earth. c.Moon.
c.Moon.
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At equilibrium on a bathroom weighting scale, the downward pull of gravity on you is balanced by a.your mass. b.an upward support force. c.your weight.
b.an upward support force.
question
question
A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car? a.1000 kg b.3000 kg c.500 kg d.1500 kg e.none of these
d.1500 kg
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Nellie pulls 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? a.30 m/s2 b.3.0 m/s2 c.10 m/s2 d.0.3 m/s2 e.300 m/s2
b.3.0 m/s2
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A force of 1 N accelerates 1-kg box at the rate of 1 m/s2. The acceleration of a 2-kg box by a net force of 2 N is a.half as much. b.the same. c.twice as much. d.none of the above
b.the same.
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A boulder following a straight-line path at constant velocity has a.a net force acting upon it in the direction of motion. b.no forces acting on it. c.zero acceleration. d.none of the above
c.zero acceleration.
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A skydiver steps from a helicopter and falls for a few seconds until terminal velocity is reached. Thereafter, until he opens his parachute, his acceleration a.increases. b.decreases. c.is constant. d.is zero. e.none of the above
d.is zero.
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A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is then a.500 N upward. b.300 N upward. c.800 N downward. d.500 N downward. e.300 N downward.
b.300 N upward.
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Two tennis balls fall through the air from a tall building. One of them is filled with lead pellets. The ball to reach the ground first is the a.lead-filled ball. b.regular ball. c.same for both
question
Consider a business jet of mass 28000kg in takeoff when the thrust for each of two engines is 28000N . Find its acceleration. Express your answer to two significant figures and include the appropriate units.
a = 2.0 m/s^2
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Consider a mass of 1 kg accelerated 1 m/s2 by a force of 1 N. Find the acceleration for a force of 2 N acting on 2 kg. Express your answer to one significant figure and include the appropriate units.
a = 1 m/s^2
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One pound is the same as 4.45 newtons. What is the weight in pounds of 1 newton? Express your answer with the appropriate units.
W = 0.220 lb
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A heavy block at rest is suspended by a vertical rope. When the block accelerates upward by the rope, the rope tension a.is greater than its weight. b.equals its weight. c.is less than its weight.
a.is greater than its weight.
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A single brick falls with acceleration g. The reason a double brick falls with the same acceleration is a.an experimental fact tested many times. b.its ratio of force to mass is the same. c.that in free fall all accelerations are g. d.none of the above
b.its ratio of force to mass is the same.
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A bowling ball and a baseball accelerate equally when falling in a vacuum because a.the force of gravity does not act in a vacuum. b.their velocities are the same. c.the force of gravity is the same for each in a vacuum. d.the ratio of their weights to mass is the same. e.none of the above
d.the ratio of their weights to mass is the same.
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A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first? a.The heavy man b.Both should arrive at the same time. c.The light woman d.not enough information
c.The light woman
question
A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to the ground first? a.The light woman b.Both should arrive at the same time. c.not enough information d.The heavy man
d.The heavy man
question
A 1-kg rock that weighs 10 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is a.less than 10 N. b.10 N. c.more than 10 N.