Physics Test 1 (Ch 1-10)
Consider a 100kg box of tools in the location A, B, and C 1) From greatest to least, rank the masses of the 100kg box of tools 2) From greatest to least, rank the weights of the 100kg box of tools
1) ABC (overlapped) 2) C, A, B
Three balls of different masses are thrown straight upward with initial speeds as indicated 1) From fastest to slowest, rank the speeds of the balls 1s after being thrown 2) From greatest to least, rank the accelerations of the balls 1s after being thrown. Or are the accelerations the same?
1) C, A, B 2) CAB (all the same)
Boxes of various masses are on a friction free, level table 1) From greatest to least, rank the net forces on the boxes 2) From greatest to least, rank the accelerations of the boxes
1) C, B, D, A 2) D, B, A, C
What is the net force acting on a 1kg ball in free fall?
10.0 N
What is the momentum of a 7.8 kg bowling ball rolling at 2.4 m/s?
19 kg x m/ s
Which of the following are scientific hypotheses? 1. Earth rotates about its axis because living things need an alternation of light and darkness. 2. Chlorophyll makes grass green. 3. Tides are caused by the Moon.
2 and 3
If you push a crate horizontally with 100 N across a 10-m factory floor and the friction between the crate and the floor is a steady 70 N, how much kinetic energy does the crate gain?
300 J
A different scaffold that weighs 400 N supports two painters, one 500 N and the other 400 N. The reading in the left scale is 800 N. What is the reading in the right-hand scale?
500 N
Lucy Lightfoot stands with one foot on one bathroom scale and her other foot on a second bathroom scale. Each scale reads 360 N. What is Lucy's weight?
720 N
What is the net force acting on a falling 1 kg ball if it encounters 2N of air resistance?
8.00 N
A boxer can hit a heavy bag with great force. Why can't he hit a piece of tissue paper in midair with the same amount of force? A) The boxer can only hit the tissue paper with a force as large as the tissue paper can exert on the boxer, and the low-mass tissue can only exert a weak force B) The tissue paper can only exert a force on the boxer as large as the air resistance force exerts on the paper C) The low-mass tissue exerts a smaller reaction force on the boxer than the action force the boxer exerts on the tissue D) The low-mass tissue floating in the air exerts no reaction force on the boxer
A
Cassy can get more force on the bricks she breaks with a blow of her bare hand when _______. A) Her hand is made to bounce from the bricks B) She toughens her hand beforehand C) She exerts follow-through D) Does so with great determination
A
Energy cannot be _____. A) Destroyed B) Transformed C) Transferred, transformed, or destroyed D) Transferred
A
In terms of impulse and momentum, why do air bags in cars reduce the chances of injury in accidents?
Air bags increase the time the force is applied and decrease the force, so the result is a lesser force for a longer time period.
A boxer rides with the punch so as to reduce ____. A) Momentum B) Force C) Impulse D) Speed
B
A pair of action-reaction forces always A) act on the same object. B) occur simultaneously. C) comprise a pair of interactions. D) all of the above E) none of the above
B
A slowly moving ship can have a greater momentum than a fast-moving racing car when _______. A) Its mass is greater than the mass of the car B) The mass times velocity is greater than that of the car C) Its speed is greater than the speed of the car D) It drifts toward a distant port
B
Acceleration is generally defined as the time rate of change of velocity. When can it be defined as the time rate of change of speed? A) When moving in a circle, the time rate of change of speed is called average speed B) When moving in a straight line, the time rate of change of speed is acceleration C) When moving in a circle, the time rate of change of speed is always zero D) When moving in a straight line, the time rate of change of speed is called velocity
B
Consider hitting a baseball with a bat. If we call the force on the bat against the ball the action force, identify the reaction force. A) The reaction force is zero because the force of the bat on the ball is equal and opposite to the force of the ball on the bat B) The reaction force is the force by the ball on the bat C) The reaction force is the force due to compression inside the ball D) The reaction force is the force of the bat on the ball
B
Consider the system of a single football. If you kick it, is there a net force to accelerate the system? If a friend kicks it at the same time with an equal and opposite force, is there a net force to accelerate the system? A) If you kick the football, or if you and you friend kick it, in both cases there is a net force to accelerate the system B) If you kick the football, there is a net force to accelerate the system; if you and you friend kick it, there is not C) If you kick the football, there is no net force to accelerate the system due to the force applied by the football on you. If you and you friend kick the football, there is a net force D) If you kick the football, there is no net force to accelerate the system due to the force applied by the football on you. The same thing applies if you and your friend kick the ball
B
Fill in the blanks: Newton's first law is often called the law of ____; Newton's second law is the law of ____; and Newton's third law is the law of ____. A) Acceleration, inertia, action-reaciton B) Inertia, acceleration, action-reaction C) Inertia, net force, friction D) Action, inertia, force
B
Select the correct equations that show that a freely falling rock drops a distance of 80m when it falls from rest for 4s A) s=g^2⋅t/2=(10m/s^2)^2⋅(4s)/2= 80m B) s=g⋅t^2/2=(10m/s^2)⋅(4s)^2/2= 80m C) s=t^2/(2⋅g)=(4s)^2/(2⋅(10m/s^2))= 80m D) s=g⋅t/2=(10m/s^2)⋅(4s)/2= 80m
B
Sine 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) Yes B) No
B
The work that is done when twice the load is lifted twice the distance is _______. A) The same B) Four times as much C) Three times as much D) Twice as much
B
What did Galileo discover in his legendary experiment on the Leaning Tower of Pisa? A) Galileo found that air resistance significantly slowed falling stones B) Galileo found that a heavier stone does not fall significantly faster than a lighter one C) Galileo found that a heavier stone falls significantly faster than a lighter one D) Galileo found that stones fall faster proportional to their weight
B
What does it mean to say something is in mechanical equilibrium? A) An object in mechanical equilibrium must experience no forces B) An object in mechanical equilibrium experiences a zero net force C) An object in mechanical equilibrium is always in motion D) An object in mechanical equilibrium experiences a net force twice its weight
B
What is the acceleration of a car that maintains a constant velocity of 100 km/h for 10s? A) 1 km/hs B) 0 km/hs C) 10 km/hs D) 0.1 km/hs
B
What relationship between distance traveled and time did Galileo discover for freely falling objects released from rest? A) Galileo discord that distance increased inversely proportional to time B) Galileo discord that distance increased as the time squared C) Galileo discord that distance was independent of time D) Galileo discord that distance increased proportional to time
B
What type of path does a moving object follow in the absence of a force? A) It follows a parabolic trajectory in the absence of a force B) It continues to move in a straight line at a constant speed C) It follows a circular path in the absence of a force D) It moves in a straight line and eventually slows to a stop
B
What will the kinetic energy of a pile driver ram be if it starts from rest and undergoes a 10 kJ decrease in potential energy? A) -10 kJ B) 10 kJ C) 5 kJ D) 0 kJ
B
When hitting a tennis ball with your racquet, the force on the ball has the same magnitude as the force on the _______. A) Player B) Racquet C) Hand that holds the racquet D) Racquet, and in the same direction
B
When you stand at rest on a bathroom scale, how does your weight compare with the support force from the scale? A) The support force from the scale is twice your weight B) Your weight is equal in magnitude and opposite in direction to the support force from the scale C) Your weight is equal in magnitude and in the same direction as the support force from the scale D) The support force from the scale is half your weight
B
Why are students of the arts encouraged to learn about science and science students encouraged to learn about the arts? A) Scientists need to learn how to write and writers need to learn what is impossible to do according to science B) Knowing both the arts and sciences makes for a wholeness in the way we view the world C) Scientists need to relax by viewing art and artists need the discipline of learning science D) Scientists need to learn to draw and artists need to learn how to solve equations
B
Why do we say that a force is a vector quantity? A) A force is a scalar quantity B) A force has a magnitude and a direction C) A force has a magnitude, but not a direction D) A force is measured in pounds, and pounds are a vector quantity
B
Which exerts the greater impulse on a steel plate: machine gun bullets bouncing from the plate or the same bullets squashing and sticking to the plate?
Bullets that bounce because the large impulse requires the change in direction.
A vertical vector of 3 units combined with a horizontal vector of 4 units has a resultant of A) 7 units B) 1 unit C) 5 units
C
According to the parallelogram rule, what quantity is represented by the diagonal of a constructed parallelogram? A) The diagonal is 1.41 times the magnitude of the longest vector B) The diagonal is the difference of two vectors C) The diagonal is the resultant, or sum, of two vectors D) The diagonal is aways 1.41 times the magnitude of the sum of the vectors
C
If an input of 100 J in a pulley system increases the potential energy of a load by 60 J, what is the efficiency of the system? A) 100% B) 40% C) 0% D) 60%
D
If you push on a crate with a horizontal force of 100 N and it slides at constant velocity, what is the magnitude and direction of the frictional force acting on the crate? A) The frictional force has nothing to do with you pushing on the crate B) The frictional force on the crate is zero N C) The frictional force on the crate is 100 N in the same direction as the direction of motion D) The frictional force on the crate is 100 N opposite the direction of motion
D
In daily life, people are often praised for maintaining some particular point of view, for the "courage of convictions." A change of mind is seen as a sign of weakness. How is this different in science? A) Scientific laws are decided to be true by majority vote B) When a famous scientist restates a law, then the old law must be abandoned C) Once a scientific law is discovered, it never changes so you must change your mind to believe it D) When a scientist finds evidence that contradicts a law, then the law must be abandoned
D
What exactly is meant by a "freely falling" object? A) An object in free falls with constant speed B) An object in free falls with constant velocity C) An object in free falls under gravity in air with air resistance but no other resistance D) An object in free falls under gravity alone with no friction
D
What is the role of equations in this book? A) Equations are interesting side notes about scientific concepts B) Equations will be derived to make you understand science C) Equations are for plug-and-chug calculations D) Equations are guides to thinking and show connections between concepts
D
When a ball falls downward, it may have a net force A) equal to its weight B) Of zero C) Equal to its weight minus air drag D) Any of the above E) None of the above
D
Suppose that a freely falling object were somehow equipped with a speedometer. By how much would it's reading in speed increase with each second of fall?
Each second the speed would increase by 10 m/s
How much impulse stops a 50-kg carton sliding at 4.4 m/s when it meets a rough surface?
J = 220 N x s
A force of gravity pulls downward on a book on a table. What force prevents the book from accelerating downward?
Normal Force
You are driving north on a highway. Then, without changing speed, you round a curve and drive east. Does your velocity change? Do you accelerate? Explain.
The acceleration does not change, but the velocity does. Constant velocity means that there is a constant speed and direction, and in this example the speed is constant but the direction is changing.
If a ball is projected upward from the ground with 10 kg m/s momentum, what is the momentum of recoil of the world? Why do we not feel this?
The change of momentum of the Earth will be equal and opposite: 10 kg m/s. The Earth is giant, so this change in momentum will produce a small change in the speed of the Earth.
Calculate the weight in N of a 1700kg elephants
W = 1.7 x 10^4 N
Calculate the acceleration of a 350000 kg jumbo jet just before takeoff when the thrust on the aircraft is 120000 N
a= 0.34 m/s^2
What impulse occurs when an average force of 10N is exerted on a cart for 2.7s
p = 27 kg x m/ s
Use d= 1/2gt^2 and solve for the time one spends moving upward in a 0.6m vertical jump. Then double it for the "hang time" - the time one's feet are off the ground
t = 0.70s
A 5.4 kg fish swimming 1.0 m/s swallows an absentminded 1.0 kg fish swimming toward it at a speed that brings both fish to a halt immediately after lunch Find the speed of the approaching smaller fish before lunch
v = 5.4 m/s
An ostrich egg of mass m is tossed at a speed v into a sagging bed sheet and is brought to rest in a time t 1) Find the force acting on the egg when it hits the sheet 2) If the mass of the egg is 0.50 kg, its initial speed is 2.2 m/s, and the time to stop is 0.20 s, find the average force on the egg
1) F= mv/t 2) F = 5.5N
A ball is tossed with enough speed straight up so that it is in the air several seconds. Assume upward direction is positive and downward is negative. 1) What is the velocity of the ball when it reaches its highest point? 2) What is its velocity 1s before it reaches its highest point? 3) What is the change in its velocity during this 1s interval? 4) What is its velocity 1s after it reaches its highest point? 5) What is the change in velocity during this 1s interval? 6) What is the change in velocity during the 2s interval (Careful!) 7) What is the acceleration of the ball during any of these time intervals? 8) What is the acceleration of the ball at the moment the ball has zero velocity?
1) v= 0 m/s 2) v= 10.0 m/s 3) Δv =-10.0 m/s 4) v= -10.0 m/s 5) Δv= -10.0 m/s 6) Δv= -20.0 m/s 7) a= -10.0 m/s^2 8) a= -10.0 m/s^2
As you read this in your chair, how fast are you moving relative to the chair? Relative to the Sun? A) You are not moving relative to the chair, but you are moving over 100,000 km/h relative to the Sun B) You are not moving relative to the chair, and you are not moving relative to the Sun C) You are moving over 100,000 km/h relative to the chair and the Sun D) You are stationary relative to the Sun, but you are moving relative to the chair
A
Fossil fuels, hydroelectric power, and wind power ultimately get their energy from _______. A) the Sun B) Greenhouse gases C) Potential energy D) Earth's nuclear energy
A
Must people choose between science and religion? A) No, there is no contradiction in being scientific and religious in one's thinking B) Yes, religion and science are completely antithetical C) No, scientific and religious beliefs and incompatible D) No, religion and science are essentially the same
A
Select the correct equations that show that the average speed of a rabbit that runs a distance of 24m in a time of 2s is 12 m/s. A) v= s/t = (24m)/(2s)= 12 m/s B) v= s^2/t = (24m)^2/(2s)= 12 m/s C) v= s x t = (24m) x (2s) = 12 m/s D) v=s/t^2 = (24m)/(2s)^2 = 12 m/s
A
Shake something to and fro and you're measuring its what? Lift it against gravity and you're measuring its what? A) Shaking measures mass, whereas lifting measures weight B) Shaking measures weight, whereas lifting measures mass C) Shaking measures neither mass nor weight. Lifting measures weight D) Shaking and lifting both measure weight
A
To produce an acceleration to a system there A) Must be a net force on the system B) Must be acceleration outside the system also C) May or may not be a net force on the system
A
Wha tis the net force on an object in either static or dynamic equilibrium? A) The net force is zero B) The net force is for static equilibrium and horizontal for dynamic equilibrium C) The net force is zero for static equilibrium and greater than zero for dynamic equilibrium D) The net force is equal and opposite to the weight of the object
A
What are steps of the scientific method? A) Hypothesis, predictions, and experimental findings B) Using Occam's razor to eliminate excess facts C) Assembling and organizing facts and checking them against dogma D) Reasoning and derivation from axioms
A
What is the net force on a cart that is pulled to the right with 100 pounds of force and to the left with 30 pounds of force? A) The net force is 70 pounds to the right B) The net force is zero C) The net force is 130 pounds D) The net force is 70 pounds to the left
A
What is the test for whether a hypothesis is scientific or not? A) A hypothesis is scientific if it is possible to prove it wrong B) A hypothesis is scientific if it can be written as an equation C) A hypothesis is scientific if the appropriate scientific body says it is D) A hypothesis is scientific if it is possible to prove it right
A
What relationship between the Sun and Earth did Copernicus formulate? A) The Earth revolved in a circle around the Sun B) The Sun and the Earth revolve in circles around each other C) The Sun revolved in a circle about the Earth D) The Earth was at rest with respect to the Sun
A
When one does twice the work in twice the time, the power expended is _______. A) The same B) Four times as much C) Three times as much D) Twice as much
A
When the useful energy output of a simple machine is 100 J, and the total energy input is 200 J, the efficiency is ______. A) 50% B) 200% C) 100% D) 75%
A
Which is more likely to break: a hammock stretched tightly between a pair of trees or one that sags more when you sit on it? A) The hammock stretched tightly between a pair of trees is more like to break B) Both hammocks are equally likely to break C) The hammock that sags more when you sit on it is more likely to break
A
Why is physics considered to be the basic science? A) Because all other sciences can be shown to be derived from it B) Physics is about how atoms combine to form molecules C) As physicist Paul Tipler says about sciences other than physics, "What other sciences?" D) Physics involved matter that is alive
A
If a car is moving at 90 km/h and it rounds a corner, also at 90 km/h, does it maintain a constant speed? A constant velocity? A) It maintains a constant velocity, but not a constant speed B) It does not maintain a constant speed or a constant velocity C) It maintains a constant speed, but does not maintain a constant velocity D) It maintains a constant speed and a constant velocity
C
If the forces that act on a cannonball and the recoiling cannon from which it is fired are equal in magnitude, why do the cannonball and cannon have very different accelerations? A) The force from the cannon ball on the cannon produces little acceleration because it lasts for such a brief time B) The cannon pushes on the cannon ball with a much greater force than the cannon ball pushes on the cannon C) Remember F=ma, and note that the cannon has a much greater mass than the cannon ball, so the cannon accelerates less for the same force D) The cannon weighs so much that friction with the ground alone prevents it from accelerating
C
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 is zero B) The acceleration triples C) The acceleration is reduced to 1/3 of its original value D) The acceleration remains the same
C
If the system is considered to be the apple and the orange together , is there a net force on the system when the apple pulls (ignoring friction with the floor)? A) Yes, the action of the apple is on the orange, so the net force is not zero B) Yes, there is a net force because the orange must accelerate when pulled C) The net force is zero because the action and reaction forces are equal and opposite D) There is no net force because the system is frictionless
C
Once the crate is sliding, how hard do you push to keep it moving at constant velocity? A) You no longer need to push once the crate is sliding B) You push with a force slightly greater than the static friction force 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
State the equilibrium rule for forces in symbolic notation A) ΣF= mg B) ΣF= net force C) ΣF= 0 D) ΣF= 2 mg
C
Suppose a ball of putty moving horizontally with 1 kg·m/s of momentum collides with and sticks to an identical ball of putty moving vertically with 1 kg·m/s of momentum. What is the magnitude of their combined momentum? A) 0kg x m/s B) 2 kg x m/s C) 1.41 kg x m/s D) 1 kg x m/s
C
Two cars are raised to the same elevation on service-station lifts. If one car is twice as massive as the other, compare their gains of potential energy. A) The less massive car has equal and opposite change of potential energy compared to the more massive car B) The car with twice the mass has half the gain of potential energy C) The car with twice the mass has twice the gain of potential energy D) Both cars have the same gains of potential energy
C
What is the net force on a bag pulled down by gravity with a force of 18 newtons and pulled upward by a rope with a force of 18 newtons? A) The net force is 18 N B) The net force is 25 N C) The net force is zero N D) The net force is 36 N
C
What kind of speed is registered by an automobile speedometer? A) Minimum speed B) Maximum speed C) Instantaneous speed D) Average speed
C
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 frontal area and speed D) The force depends mostly on g and mass
C
What two units of measurement are necessary for describing speed? A) Average speed and time B) Average speed and distance C) Distance and time D) Distance and length
C
When a big fish swims into an oncoming smaller fish and swallows it, the momentum of the two-fish system _______. A) Converts to spurious motion B) Decreases C) Remains the same D) Increases
C
When the Sun was directly overhead is Syene, why wasn't it directly overhead in Alexandria? A) Gravity bends light B) The Sun is a sphere C) The Earth is a Sphere D) Syene is in a different time zone than Alexandria
C
When traveling twice as fast your kinetic energy is increased _____. A) By a factor of two B) By a factor of three C) By a factor of four D) Not at all
C
When two vehicles collide, momentum is conserved ______ A) Only if deformation of either vehicle does not occur B) If the collision is elastic C) Whether the collision is elastic or inelastic D) If the collision is inelastic
C
When you lift twice the load twice as high, in half the time, the increase in potential energy is _______. A) Three times B) The same C) Four times D) Twice as much
C
Which is normally greater: static friction or sliding friction on the same object? A) On the same object, station and dynamic friction are equal B) Dynamic friction is normally greater than static friction C) Static friction is normally greater than dynamic friction D) Static friction and dynamic friction are both zero
C
Why doesn't a heavy object accelerate more than a light object when both are freely falling? A) The larger air resistance force o the larger object makes it fall with the same acceleration 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 ratio of the weight to mass is the same for all objects in the same locality D) The inertia of the heavy object equals the inertia of the lighter object, so their accelerations are the same
C
A track is made of a piece of channel iron bent as shown. A ball released at the left end of the track continues past the various points. Rank the speed of the ball at points A, B, C, and D, from fastest to slowest. Watch for tie scores.
C, BD, A
How does acceleration depend on the net force? A) Acceleration is inversely proportional to the net force B) Acceleration is equal to the net force C) Acceleration is independent of the net force D) Acceleration is proportional to the net force
D
How does the force of friction for a sliding object vary with speed? A) The force of friction is zero for a sliding object B) The force of friction is proportional to speed C) The force of friction is inversely proportional to speed D) The force of friction is approximately independent of speed
D
In daily life, we see many cases of people who are caught misrepresenting things and who soon thereafter are excused and accepted by their contemporaries. How is this different in science? A) A scientist who makes a mistake is never allowed to be a scientist again B) A scientist who disagrees with a current theory is never allowed to be a scientist again C) A scientist who proposes a hypothesis that is eventually disproven is never allowed to be a scientist again D) A scientist who lies in a scientific publication will suffer professional excommunication
D
In the apple-pulling-the orange sequence in this chapter, what is the force that accelerates the system across the floor? A) Internal forces B) The backwards pull by the orange C) The resistance to motion by the orange D) Friction between the apple and the floor
D
In which is momentum conserved: an elastic collision or an inelastic collision? A) Momentum is conserved in neither elastic nor inelastic collisions B) Momentum is conserved only in inelastic collisions C) Momentum is conserved only in elastic collisions D) Momentum is conserved in elastic and inelastic collisions
D
Select the correct equations that show that the acceleration of a hamster is 5 m/s^2 when it increases its velocity from 10 m/s in 2s A) a=Δv/t2=(10m/s)/(2s)^2=5m/s^2 B) a=Δv⋅t=(10m/s)⋅(2s)=5m/s^2 C) a=(Δv)^2/t=(10m/s)^2/(2s)=5m/s^2 D) a=Δv/t=(10m/s)/(2s)=5m/s^2
D
The quantity that is called impulse can be measured by the _______. A) How long the force acts compared to the amount of time B) Addition of force and time C) Difference between force and time D) Product of force and time
D
Wha tis the distance fallen for a freely falling object 2s after being dropped from a rest position? What is the distance for a 4s drop? A) It falls 5m in 1s and 20m in 4s B) It falls 10m in 1s and 160m in 4s C) It falls 5m in 1s and 5m in 4s D) It falls 5m in 1s and 80m in 4s
D
What are the units for force? A) Force must be measured in pounds and then converted to newtons B) Force must be measured in newtons; it can never be measured in pounds C) Force must first be measured in newtons, then converted to pounds D) Force can be expressed in newtons or pounds
D
What did Galileo discover about moving bodies and force in his experiments with inclined planes? A) Bodies rolling down an inclined plane slowed down B) Bodies rolling up an inclined plane sped up C) Bodies rolling down a steep inclined plane starting at a given height rolled up a gently inclined plane to a higher height D) In the absence of a retarding force, a body will keep moving at a constant speed in a straight line forever
D
