Physics final

FH=

-Fsp

Which of these is a larger temperature difference ? The are all the same 1K 1 ° C and 1 K are the same and larger than 1 ° F 1 ° C 1 ° F

1 ° C and 1 K are the same and larger than 1 ° F

Usp-Elasric/spring energy

1/2k(change in X)^2

Students A and B do the same amount of work , but B does it in twice the time . A's power output is 4 times B 2 times B 1/4 of B half of B Their power output is the same .

2 times B

A cat is batting at 2 balls , a red one and a blue one . The red ball has twice the mass of the blue ball . The cat hits both balls with the same force . The acceleration of the blue ball is 4 times the acceleration of the red ball Not enough information to draw any conclusions the same as the acceleration of the red ball 2 times the acceleration of the red ball ½ of the red ball

2 times the acceleration of the red ball

You throw a ball straight up in the air with a velocity v ( kinetic energy K ) and it reaches a height H. How high will the ball rise if the initial speed is tripled ? 9H not enough information to say 3H √3H

9H

A merry - go - round spins freely when Diego moves quickly to the center along a radius of the merry - go round . As he does this , it is true to say that A ) the moment of inertia of the system decreases and the angular speed increases . B ) the moment of inertia of the system decreases and the angular speed decreases . C ) the moment of inertia of the system decreases and the angular speed remains the same . D ) the moment of inertia of the system increases and the angular speed increases . E ) the moment of inertia of the system increases and the angular speed decreases .

Answer : A

As a spring is stretch a greater distance the force of the spring on your hand A ) Increases B ) Decreases C ) Stays the same D ) There is not enough information to tell

Answer : A

20 ) A 5 - kg ball collides inelastically head - on with a 10 - kg ball , which is initially stationary . Which of the following statements is true ? ( There could be more than one correct choice . A ) The magnitude of the change of velocity the 5 - kg ball experiences is greater than that of the 10 - kg ball . B ) The magnitude of the change of velocity the 5 - kg ball experiences is less than that of the 10 - kg ball . C ) The magnitude of the change of velocity the 5 - kg ball experiences is equal to that of the 10 - kg ball . D ) The magnitude of the change of the momentum of the 5 - kg ball is equal to the magnitude of the change of momentum of the 10 - kg ball . E ) Both balls lose all their momentum since the collision is inelastic.

Answer : A , D

7 ) You are standing on a skateboard , initially at rest . A friend throws a very heavy ball towards you . You have two choices about what to do with the ball : either catch the ball or deflect it back toward your friend with the same speed as it was originally thrown . Which choice should you make in order to maximize your speed on the skateboard ? A ) Catch the ball . B ) Deflect the ball back . C ) Your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the

Answer : B

11 ) A large 75 - kg lighting fixture can be hung from wires of identical size and shape made of aluminum , brass , or copper . The values of Young's modulus for these metals are 0.70 × 1011 Pa ( aluminum ) , 0.91 × 1011 ( brass ) , and 1.1 x 1011 ( copper ) . Which wire would stretch the least distance ? A ) aluminum B ) brass C ) copper D ) They will all stretch the same distance .

Answer : C

14 ) Two wires are made out of the same metal , but one wire is twice as long as the other wire . Which wire will have the greatest elastic modulus ? A ) the shorter wire B ) the longer wire C ) It will be the same for both wires

Answer : C

5 ) When a car is weighed , it is driven slowly on a horizontal floor over a scale that records a reading as the front wheels go over the scale , and then records a second reading as the rear wheels go over the scale . The weight of the car is equal to A ) the weight under the front wheels . B ) the weight under the rear wheels . C ) the average of the two weights . D ) the sum of the two weights . E ) the difference of the two weights .

Answer : D

Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct ? A ) Both do positive work , but person X does four times the work of person Y. B ) Both do positive work , but person X does twice the work of person Y. C ) Both do the same amount of positive work . D ) Both do zero work . E ) Both do positive work , but person X does one - half the work of person Y.

Answer : D

The temperature in your classroom is closest to A ) 68 K. B ) 68 ° C . C ) 50 ° C . D ) 295 K.

Answer : D

Joe and Bill throw identical balls vertically upward . Joe throws his ball with an initial speed twice as high as Bill . If there is no air resistance the maximum height of Joe's ball will be A ) four times that of Bill's ball . B ) two times that of Bill's ball . C ) equal to that of Bill's ball . D ) eight times that of Bill's ball . E ) roughly 1.4 times that of Bill's ball .

Answer A

Two objects , one of mass m and the other of mass 2m , are dropped from the top of a building . If there is no air resistance , when they hit the ground A ) both will have the same kinetic energy . B ) the heavier one will have twice the kinetic energy of the lighter one . C ) the heavier one will have four times the kinetic energy of the lighter one . D ) the heavier one will have half the kinetic energy of the lighter one . E ) the heavier one will have one - fourth the kinetic energy of the lighter one .q

Answer B

A tiger is running in a straight line . If we double both the mass and speed of the tiger , the magnitude of its momentum will increase by what factor ? A )√2 B ) 2 C ) 4 D ) 8 E ) 16

Answer C

When you drop a pebble from height H , it reaches the ground with speed V if there is no air resistance . From what height should you drop it so it will reach the ground with twice speed ? A ) √2H B ) 2H C ) 4H D ) 8H E ) 16H

Answer C

14 ) You and your friend , who weighs the same as you , want to go to the top of the Eiffel Tower . Your friend takes the elevator straight up . You decide to walk up the spiral stairway , taking longer to do so . Compare the gravitational potential energy of you and your friend , after you both reach the top . A ) It is impossible to tell , since the times you both took are unknown . B ) It is impossible to tell , since the distances you both traveled are unknown . C ) Your friend's gravitational potential energy is greater than yours , because he got to the top faster . D ) Both of you have the same amount of gravitational potential energy at the top . E ) Your gravitational potential energy is greater than that of your friend , because you traveled a greater distance in getting to the top .

Answer D

A lightweight object and a very heavy object are sliding with equal speeds along a level frictionless surface They both slide up the same frictionless hill with no air resistance . Which object rises to a greater height ? A ) The heavy object , because it has greater initial kinetic energy . B ) The light object , because gravity slows it down less . C ) The lightweight object , because the force of gravity on it is less . D ) The heavy object , because it has more mass to carry it up the hill . E ) They both slide to exactly the same height .

Answer E

Which one of the following is a true statement ? A ) The second law of thermodynamics is a consequence of the first law of thermodynamics . B ) It is possible for heat to flow spontaneously from a hot body to a cold one or from a cold one to a hot one depending on whether or not the process is reversible or irreversible . C ) It is not possible to convert work entirely into heat . D ) It is impossible to transfer heat from a cooler to a hotter body . E ) All of these statements are false .

Answer E

You are trying to spin a wheel on a bike to look for a flaw in the tire . The tire is not in contact with the ground . Which the following force applications will result in the largest torque on the wheel if all forces have the same magnitude ? At the outer edge perpendicular to the radius of the tire Halfway between the axle and the outer edge perpendicular to the radius None of these create a torque At the outer edge at a 45 ° angle to the radius of the tire All the choices produce the same torque .

At the outer edge perpendicular to the radius of the tire

Entropy of an isolated system

Can't decrease

Impulse =

Change in P, Favg change in time

Power=

Change in energy over change in time

37 ) If the units of your answer are kg m2 / s3 , which of the following types of quantities could your answer ( There could be more than one correct choice .) A ) kinetic energy B ) potential energy C ) force D ) power E ) work

D

Two small balls with the same mass attract each other gravitationally with a force of F. If the mass of each ball is decreased by a factor of 1/2 , but the distance between them remains the same , what is the magnitude of the gravitational force on each one ? F / 2 F 4F F / 4 2F

F / 2

Two small balls with the same mass attract each other gravitationally with a force of F. If the distance between the balls is tripled , but the masses remain the same , what is the magnitude of the gravitational force on each one ? F F / 9 F / 3 3F 9F

F / 9

Young's Modulus

F = YA/L, Change in L=F/y*L/A

W =

Fd cos theta

Two carts on a frictionless track collide and stick together . Which statement is true ? Final total momentum is equal to initial total momentum Final total momentum is less than initial total momentum All of these could be true . It depends on the masses . Final total momentum is greater than initial total momentum

Final total momentum is equal to initial total momentum

The ISS ( International Space Station ) orbits the Earth in a circular orbit . If gravity could be turned off with a switch , what would happen to the ISS ? It would move in a straight line in the direction it was going when gravity was turned off . Not enough information to say . It would transition to a larger circular orbit . It would move radially outward from the Earth . It would fall into the Earth

It would move in a straight line in the direction it was going when gravity was turned off .

The normal force on a stationary box with mass M on an incline at an angle 9 to the horizontal is Mg tanθ Mg Mg cosθ Mg ( 1 + sinθ ) Mg sinθ

Mg cosθ

Momentum is conserved if

No outside forces affecting interaction.

In an elastic collision

P is conserved and K is conserved

A red ball and a blue ball have the same mass . They are dropped from the same height . The red ball bounces very well , but the blue ball sticks to the floor and doesn't bounce at all . Which statement below true about their interactions with the floor ? none of these are true . Both balls experience the same change of momentum . The blue ball has a smaller change of momentum than the red ball . The red ball has a smaller change of momentum than the blue ball .

The blue ball has a smaller change of momentum than the red ball .

A 1 kg book and a 2 kg book are lifted individually from a table to the same shelf . What can be said about the change of gravitational potential energy of both ? The change for the 2 kg book is 2 times the change for the 1 kg book . They have the same change of potential energy . The change for the 1 kg book is 4 times the change for the 2 kg book . The change for the 2 kg book is 4 times the change for the 1 kg book . The change for the 1 kg book is 2 times the change for the 2 kg book .

The change for the 2 kg book is 2 times the change for the 1 kg book .

A train collides with a crate of rubber ducks that was left on the tracks . What force does the crate exert on the train ? The crate exerts no force on the train . The crate exerts less force on the train than the train exerts on the crate . The crate exerts the same force on the train that the train exerts on the crate . Not enough information to say . The crate exerts more force on the train than the train exerts on the crate .

The crate exerts the same force on the train that the train exerts on the crate .

A disk is spinning about its center at a constant rate . A blue dot is at the edge of the disk and a orange dot is halfway between the edge and the center . What can be said about the motion of the dots ? The dots have the same angular and tangential velocity Not enough information to compare the motion of the dots . The dots have the same angular velocity , but the blue dot has a larger tangential velocity The dots have the same tangential velocity , but the blue dot has larger angular velocity The blue dot has a larger angular and tangential velocity

The dots have the same angular velocity , but the blue dot has a larger tangential velocity

lo is one of Jupiter's moons . Which one experiences a larger gravitational force ? The answer depends on how far apart they are lo because Jupiter is so much more massive They experience the same gravitational force Jupiter because lo is smaller

They experience the same gravitational force

A bicycle is traveling on a flat road at 3.2 m / s . What is the linear speed at the top and bottom of the tires on the bicycle ? Top is moving at 6.4 m / s and bottom is moving at 0 m / s . Top and bottom are both moving at 6.4 m / s . Top is moving at 6.4 m / s and bottom is moving at 3.2 m / s . Top and bottom are both moving at 3.2 m / s . Cannot determine without the radius of the tire

Top is moving at 6.4 m / s and bottom is moving at 0 m / s .

AEth =

W + Q

e =

W/Ein and W/Qh

Power unit

Watt=J/s

Entropy

a measure of the disorder of a system

A ball launcher is used in the lab to launch 3 balls at the same speed from the same height . The red ball is launched 30 ° up , the yellow ball horizontally , and the blue ball is launched 30 ° down . If there is no air resistance which ball reaches the ground with the smallest speed ? all reach the floor with the same speed Need more information to say yellow ball red ball blue ball

all reach the floor with the same speed

A car is driving up a ramp at a steady speed of 8.6 m / s . The net force acting on the car must point up the ramp point down the ramp point straight down point perpendicular to the ramp be zero

be zero

The direction of the acceleration of an object moving in a circle with a constant speed is directly toward the center of the circle opposite the velocity directly away from the center of the circle there is no acceleration The same as the velocity

directly toward the center of the circle

2nd Law of Thermo

heat flow from hot to cold spontaneously Heat engine cannot be 100% efficient

Power

how fast work done, rate of energy to transform

Water vapor condenses on the outside of a glass of iced tea . The entropy of the condensation is less than the entropy of the water vapor greater than the entropy of the water vapor depends on the temperature of the water the same as the entropy of the water vapor

less than the entropy of the water vapor

A diver is spinning in the air with her arms and legs tucked close to her torso . When she extends her arms and legs her moment of inertia decreases and angular velocity increases moment of inertia increases and angular velocity decreases moment of inertia and angular velocity increase Nothing can be said without knowing the mass of the diver . moment of inertia and angular velocity decrease

moment of inertia increases and angular velocity decreases

Doof and Shmirtz are trying unsuccessfully to move a large rock . Shmirtz pushes for 8 minutes with a force of 900 N. Doof pushes for 12 minutes with a force of 1200 N. Compare the amount of work they each do on the rock . Doof does 33 % more work Doof does 50 % more work neither does any work . Doof does 100 % more work Doof does 25 % more work

neither does any work .

You want to put a box toward the end of a board with 2 supports beneath it . What must be true for the board to not tip ? net torque is zero net torque or net force is zero net torque and net force are zero net force is zero

net torque and net force are zero

A box is moving with a constant velocity . What can be said about the forces acting on it ? the net force is perpendicular to the velocity the net force is in the direction of the motion no forces act on the box , or the net force is zero Not enough information to say anything about the forces . the net force is opposite the velocity

no forces act on the box , or the net force is zero

If you push a box across the floor with a force at an angle of 30 ° below the horizontal , how does the normal force compare to the weight of the box ? normal is less than the weight depends on the coefficient of friction normal is larger than the weight normal is equal to the weight depends on how fast it is moving

normal is larger than the weight .

You drop a tennis ball and watch it bounce . What is the sign of the work done by gravity as it falls to the floor and after it bounces up off the floor ? negative on the way down and up positive on the way down and up . negative on the way down and positive on the way up positive on the way down and negative on the way up

positive on the way down and negative on the way up

You are pulling a sled through deep snow when you stop to rest . You then try to start again . What requires a larger force , starting from rest or maintaining the motion ? Why ? maintaining the motion because μs>μk The force is the same because it is all friction starting from rest because that is when the normal force is largest starting from rest because μs>μk

starting from rest because μs>μκ

An 89 N force is applied to two copper wires . The wires are the same diameter , but one is 0.75 m long and the other is 0.85 m long . Which one stretches more ? need to know Young's modulus to answer . the 0.75 m wire they stretch the same amount the 0.85 m wire

the 0.85 m wire

Two wooden posts have the same height but different diameters , 10 cm and 15 cm . A 50 kg box is balanced on each post separately Which post will compress more ? the 10 cm post they compress the same amount the 15 cm post need to know Young's modulus to answer .

the 10 cm post