Physics final

A box of mass m is sitting of an incline of 45 degrees and it requires an applied force F up the incline to get the box to begin to move. What is the maximum coefficient of static friction? A root2F/mg - 1 B root2F/mg C root2F/mg + 1 D 2F/mg -1

A

(With diagram) If the surface of the incline is frictionless, with what speed will the block reach the bottom if it was released from rest at the top? A 8 B 10 C 14 D 18

B

Which of the following changes to a circuit will always bring about an increase in the current? A increased voltage and increased resistance B decreased voltage and decreased resistance C increased voltage and decreased resistance D decreased voltage and increased resistance

C

If each of the resistors in the circuit has a resistance of 3 ohms, what must be the end of the battery if the circuit draws a total of 3 A? A 0.3 V B 10 V C 30 V D 54 V

C

If the objects initial velocity is 2 m/s what will be the objects velocity after this force acts upon the object? A 12 B 10 C 9 D 6

C

In the figure above, the coefficient of sliding friction between the small block and the tabletop is 0.2. If the pulley is frictionless and massless, what will be the acceleration of the blocks once they are released from rest? A 0.5 g B 0.6 g C 0.7 g D 0.8 g

C

In which of the following situations involving a source of sound and a detector of the sound is it possible that there is NO perceived Doppler shift? A the source travels toward the stationary detector B the detector travels toward the stationary source C both the source and detector travel in the same direction D both the source and detector travel in opposite directions, with the source and detector moving away from each other

C

Object 1 of mass 0.25 kg moves at 10 m/s towards object 2 initially at rest of mass 0.25 kg. the resulting collision is perfectly inelastic what is the speed of the objects after the collision? A 0 B 2.5 C 5 D 7.5

C

The diagram above shows a top view of an object of mass M on a circular platform of mass 2M that is rotating counterclockwise. Assume the platform rotates without friction. Which of the following best describes an action by the object that will increase the angular speed of the entire system? A the object moves toward the center of the platform increasing the total angular momentum of the system B the object moves toward the center of the platform decreasing the rotational inertia of the system C the object moves away from the center of the platform increasing the total angular momentum of the system D the object moves away from the center of the platform decreasing the rotational inertia of the system

B

The magnitude of the impulse on the force? A 10 B 7 C 5 D 1

B

What is the distance an object covers during the interval t = 0 to t = 5s? A 25 m B 16.5 m C 15 m D 8.5 m

B

In the graph above, the instantaneous velocity at 9 seconds is closest to A 4/9 B -4/9 C 11/4 D -11/4

D

Two objects a sphere and a block of the same mass are released from rest at the top of an inclined plane. The sphere rolls down the inclined plane without slipping. the block slides down the plane without friction. Which object reaches the bottom of the ramp first? A the sphere because it gains rotational KE but the block does not B the sphere because it gains ME due to the torque exerted on it but the block does not C the block because it does not lose ME due to friction but the sphere does D the block because it doesn't gain rotational KE but the sphere does

D

Two objects are sitting on a uniform stick that pivots around its center. Object 1 has a mass of 20 kg and object 2 has a mass of 30 kg. if the object 2 sits 1m to the left of the center of th stick, how far to the right must object 1 sit in order to balance the stick? A 0.25 m B 0.5 m C 1 m D 1.5 m

D

For the circuit shown above, what is the voltage of the battery (assuming the battery has no internal resistance)? A 1 V B 5 V C 10 V D 50 V

C

A moon has an elliptical orbit about the planet as shown above... Which of the following correctly explains the method for determining the distance of the moon from the planet at point B in the given quantities? A conservation of angular momentum because the gravitational force exerted by the moon on the planet is the same as that exerted by the planet on the moon B conservation of angular momentum cuz the gravitational force exerted on the moon is always directed towards the planet C conservation of energy because the gravitational force exerted by the moon on the planet is always directed towards the planet D conservation of energy because the gravitational force exerted by the moon on the planet is the same as that exerted by the planet on the moon

A

A pair of protective headphones reduces the sound of a jet engine from 140 dB to 110 dB. What percent of the noise is being blocked? A 99.9 % B 78.6 % C 21.4 % D 0.1 %

A

A simple harmonic oscillator has a frequency of 2.5 Hz and an amplitude of 0.05 m. What is the period of the oscillations? A 0.4 s B 0.2 s C 8 s D 20 s

A

A simple pendulum executed simple harmonic motion as it swings through small angles of oscillation. If theta max denotes the amplitude of the oscillations, which of the following statements is true? A when theta = 0 the tangential acceleration is 0. B when theta = theta max the tangential acceleration is 0 C when theta = 0 the speed is 0 D when theta = 0 the restoring force is maximized

A

A small cart of mass M is initially at rest. It collides elastically with a large cart of mass 4M and velocity v. The large cart loses half its kinetic energy to the little cart. The little cart now has a velocity of A 1.41v B v C 2v D 4v

A

A sphere starts from rest at the top of s hill with a constant angle of inclination and is allowed to roll without slipping down the hill. What force provides the torque that causes the sphere to rotate? A static friction B kinetic friction C the normal force of the hill on the sphere D gravity

A

A stopper of mass M is tied to a string of length R and swings around horizontally in uniform circular motion with a velocity of v acted on by a force of F. What is the period of the stopper? A root(4pi^2MR/F) B root(MR/4pi^2F) C root(4pi^2/FMR) D root(4pi^2R/MF)

A

An object (mass = m) above the surface of the Moon (mass = M) is dropped from an altitude h equal to the Moon's radius (R). What is the object's impact speed? A root(GM/R) B root(GM/2R) C root(2GM/R) D root (2GMm/R)

A

If the coefficient of friction between the block and the incline is 0.4, how much work is done by the normal force on the block as it slides down the full length of the incline? A 0 J B 2.0 J C 4.0 J D 4.9 J

A

In the diagram above, a mass m starting at point A is projected along each of the three tracks shown here sufficient in each case to allow them ads to reach the end of the track at point B. If t1 t2 and t3 Are the total travel times between A and B for paths 1,2 and 3 respectively, what is the relation among these times? A t3 < t2 < t1 B t2 < t3 < t1 C t2 < t1 = t3 D t2 = t3 < t1

A

The figure above shows two positively charged particles. The +Q charge is fixed in position, and the +q charge is brought close to the +Q and released from rest. Which of the following graphs best depicts the acceleration of the +q charge as a function of its distance r from +Q?

A

The gravitational force the sun exerts on the earth is F. Mars is 1.5 times from the Sun than the earth and its mass 1/6. Of the earths mass. What is the gravitational force that the sun exerts on Mars? A 2/27F B 1/9F C 9 F D 27/2F

A

Two traveling waves of equal frequency, one of amplitude 4 cm and the other of amplitude 6 cm, superimpose in a single medium. Which of the following best describes the displacement D of the resultant wave? A 2cm < D < 10cm B D = 5cm C D = 10cm D 10cm < D < 12cm

A

Wire Y is made of the same material but has twice the diameter and half the length of wire X. If wire X has a resistance of R the Wire Y would have a resistance of A R/8 B R/2 C R D 2R

A

In the figure above, 4 charges are arranged. If the magnitudes of all the charges q are the same and he distance r is shown above, what is the magnitude of the net force on the bottom right?

A (most complicated)

Which of the following statements will increase the resistance of a closed circuit system? Two answers. A replacing the wire with one that has a smaller cross sectional area B adding a voltmeter to the wire C halving the wire length in the close circuit D adding another resistor in parallel with the current resistor in a closed circuit

AB

A mass on a spring and a simple pendulum undergo simple harmonic motion. There is no friction present for the mass on the string. Which of the following statements are true? Two answers. A mechanical energy is constant B the momentum of the mass is constant C the period of the mass is constant D the restoring force is constant

AC

A musician plucks a string on an acoustic guitar. Standing waves will most likely occur in which of the following media? Two answers. A the guitar string B the air surrounding the guitar C the air inside the guitar D the ground beneath the musician

AC

If the acceleration of an object is not zero, then which of the following could be constant. Two answers. A speed B linear momentum C kinetic energy D velocity

AC

An object traveling at x m/s can stop at a distance d m with a maximum negative acceleration. If the car is traveling 2x m/s which of the following statements are true. Two answers. A the stopping time is doubled B the stopping time is quadrupled C the stopping distance is doubled D the stoping distance is quadrupled

AD

The electric field strength in a vacuum at a point at a distance from a source charge is NOT dependent on which of the following? Two answers. A another charge placed at that point B the magnitude of the source charge C the distance from the source charge D the sign of the source charge

AD

A 4 kg wooden block resting on an icy surface is attached to a horizontal spring (L=1m, k = 100) high is attached on the other end to a vertical wall. A 2f bullet is fired at a speed of 100 m/s into the wooden block pushing it directly toward the wall. Which of the following best approximates the period and amplitude? A T = 1.2s and A = 45 cm B T = 1.2 s and A = 1cm C T = 0.83s and A = 45 cm D T= 0.83s and A = 21cm

B

A bubble in a glass of water releases from rest at the bottom of the glass and rises at acceleration a to the surface in t seconds. How much farther does the bubble travel in its last second than in its first second? A at B (t-1)a C (t+1)a D 1/2at

B

A person standing on a horizontal floor is acted upon by two forces: the downward pull of gravity and the upward normal force of the floor. These two forces A have equal magnitudes and form an action-reaction pair B have equal magnitudes and do not form an action-reaction pair C have unequal magnitudes and form an action-reaction pair D have unequal magnitudes and do not form an action-reaction pair

B

A projectile is launched with an initial velocity of magnitude a at an angle B to the horizontal. Find its maximum vertical displacement ignoring effects due to the air. A (a^2sin2B/2g) B (a^2/sin^2B/2g) C (a^2sin2B/g) D (a^2sin^2B/g)

B

A rope of length 60 cm is tied to the handle of a bucket whose mass is 3 kg and the bucket is then whirled in a vertical circle. At the bottom of its path, the tension in the rope is 50 N. What is the speed of the bucket at this point? A 1 B 2 C 3 D 4

B

A sound wave with frequency f travels through air at speed c. With what speed will a sound wave with frequency 4f travel through the air? A v/4 B v C 2v D 4v

B

An astronaut lands on a planet whose mass and radius are each twice that of earth. If the astronaut weighs 800 N on earth, how much will he weigh on this planet? A 200 N B 400 N C 800 N D 1600 N

B

An object is thrown horizontally off a high cliff at 7.5 m/s. What is its displacement after 2 seconds? A 27.5 m B 25 m C 20 m D 15 m

B

Consider the above configuration of masses attached via a massless rope and pulley over a frictionless incline plane. What is the acceleration of the masses? A (m1-m2)g/(m1+m2) B (m1 - m2sin)g/ (m1 + m2) C (m1 - m2cos)g/ (m1 + m2) D g

B

How much current does a 60 W light bulb draw if it operates at a voltage of 120 V? A 0.25 A B 0.5 A C 2 A D 4 A

B

If R1 were to burn out, the current coming out from the battery would A increase B decrease C stay the same D there is no current, because the circuit is now incomplete

B

If v = 100v, R1 = 50 ohms, R2 = 80 ohms and R3 = 120 ohms. Determine the voltage across R3. A 100 v B 60 v C 40 v D 20 v

B

In the figure above, are two blocks of mass 3m and 2m attached together. The plane is frictionless and the pulley is frictionless and massless. The inclined portion of the plane creates an angle theta with the horizontal floor. What is the acceleration of the block 2m if both blocks are released from rest? A 2mg B 2/5 g sin theta C 2/3 g sin theta D 3/5 g sin theta

B

The figure above shows a plane diagram. The figure shows four point charges arranged at the corners of a square with point B at its center. A positive charge would experience no net force if it were placed at which of the three points shown in the figure. A A only B B only C C only D A, B or C

B

The sun is approx 150 million km from the earth. A year- one revolution- is roughly pi x 10^7 seconds. Assuming a circular orbit, what best approximates the average acceleration of the earth due to the sun? A 6x10^-6 B 6x10^-3 C 4x10^2 D 4x10^19

B

Two equally positive charges are R distance apart. If the amount of charge on one is doubled and the distance between the charges is doubled, what is the ratio of new electric force to old electric force? A 1/4 B 1/2 C 2 D 4

B

Two objects, A and B, have equal charge and equal mass. Neither body in motion because the gravitational and electrostatic forces between them are equal. If the mass of Object A is halved, equilibrium will be maintained if A the charge in object A were doubled B the charge on object b were halved C the charge on object b were doubled D the mass on object b were halved

B

Two satellites are in circular orbit around earth. The distance from satellite 1 to earth's center is r1 and the distance rom satellite 2 to the earth's center is r2. What is the speed of satellite 2? A v1 root (r2/r1) B v1 root (r1/r2) C v1 (r2/r1) D v1 (r1/r2)^2

B

What is the objects acceleration during the interval t = 0 to t = 3s? A 0.5 B 1 C 1.5 D 2

B

Wire 1 has 3 times the length and twice the diameter of wire 2. If both wires are made of the same material and if R1 is the resistance of wire #1 and r2 is the resistance of wire #2 then which of the following is true? A R2 = 2/3R1 B R2 = 4/3 R1 C R2 = 6R1 D R2 = 12R1

B

N resisters are connected in parallel with a battery of voltage V. If one of the resistors is removed from the circuit which of the following quantities will decrease? Two answers. A the voltage across any of the remaining resistors B the current output by the battery C the power dissipated in the circuit D the voltage supplied by the battery

BC

A sound wave travels through a metal rod with wavelength lamda and frequency f. Which of the following is true? Two answers. A when this sound wave passes into air the frequency will change B when this sound wave passes into air the wavelength will change C while on the metal rod the lamda and frequency f have a direct relationship D while in the metal rod the lamda and frequency f have an inverse relationship

BD

A 100 kg object is attached to a spring mounted to the ceiling with a spring coefficient of k =100. If the string is stretched by 30m from the initial testing position with the block attached, what is its acceleration at that point? A 0 B 10 C 20 D 30

C

A 1000 kg object is hung on a string in between two identical towers that are 340m apart. The object sits 100 m below the height of the towers. What is the tension in the string? A 5 kN B 8 kN C 10 kN D 20 kN

C

A 50 kg block resting on flat ground is attached by a hook at the center of its top face to a rope, which is then pulled by a man such that it makes an angle of 30 degrees with the horizontal. If the man pulls with a force of 200 N and the coefficient of kinetic friction is 0.2, what horizontal acceleration does the block undergo? A 3.2 B 2.8 C 1.8 D 1.4

C

A ball is thrown in a projectile motion trajectory with an initial velocity v at an angle theta above the ground. If the acceleration due to gravity is -g, which of the following is the correct expression of the time it takes for the ball to reach its highest point y from the ground? A v^2sint/g B -costheta/g C vsintheta/g D v^2costheta/g

C

A beam of monochromatic light entering a glass window pane the air will experience a change in A frequency and wavelength B frequency and speed C speed and wavelength D speed only

C

A rope stretched between two fixed points can support transverse standing waves. What is the ratio of the sixth harmonic frequency to the third harmonic frequency? A 1/2 B 1/root2 C 2 D 2/root2

C

A uniform bar is lying on a flat table. Besides the gravitational and normal forces (which cancel), the bar is acted upon by two other forces, F1 and F2, which are parallel to the surface of the table. If the net force on the rod is zero, then which one of the following is true? A the net torque on the bar must also be zero B the bar can accelerate translationally if F1 and F2 are not applied at the same point C the net torque will be zero if F1 and F2 are applied at the same point. D the bar cannot accelerate translationally or rotationally

C

An alarm whose frequency is 400 Hz is dropped out of a third floor window. The student who drops it measures the frequency with a very sensitive oscilloscope. The measured frequency A appears higher than 400 Hz and the frequency increase as it falls B appears higher than 400 Hz and the frequency decreases as it falls C appears lower than 400 Hz and the frequency decreases as it falls D appears lower than 400 Hz and the frequency increases as it falls

C

An object begins at rest at the top of an inclined frictionless plane with a height of 125 m and horizontal length of 200 m. What will be the speed of the object at the end of the inclined plane? A 235 m/s B 100 m/s C 50 m/s D 23.5 m/s

C

An object of 100 kg rests on a horizontal floorZ the coefficient of static friction is 0.4 between the object and the floor. If a constant force of 250 N is pushed horizontally on the object what is the magnitude of the force of static friction? A 400 N B 350 N C 250 N D 150 N

C

An object of mass m (object 1) moving with speed v collides heads on with a target object of mass 2m (object 2) initially at rest. If the collision is perfectly inelastic what fraction of object 1's initial KE is lost? A 1/9 B 1/6 C 2/3 D 4/5

C

Sound waves travel at 350 m/s through warm air and at 3500 m/s through brass. What happens to the wavelength of a 700 Hz acoustic wave as it enters brass from warm air? A it decreases by a factor of 20 B it decreases by a factor of 10 C it increases by a factor of 10 D the wavelength remains unchanged

C

What is the net work done as the mass falls from 0 to 8 cm? A 80 J B 20 J C 0 J D -5 J

C

A 2 kg is attached to a massless 0.5 m string and is used as a simple pendulum by extending it to an angle theta = 5 degrees and allowing it to oscillate. Which of the following changes will change the period of the pendulum? Two answers. A replacing the mass with a 1 kg mass B changing the initial extension of the pendulum to a 10 degrees angle C replacing the string with a 0.25 m string D moving the pendulum to the surface of the moon

CD

A lightweight toy car crashes head on into a heavier toy truck. Which of the following statements is true as a result of the collision? Two answers. A the car will experience a greater impulse than the truck B the car will experience a greater change in momentum than the truck C the magnitude of the acceleration experienced by the car will be greater than that experienced by the truck D the total momentum in the collision will be conserved

CD

(With diagram) If the surface of the incline is frictionless, how long will the block take to reach the bottom of it was released from rest at the top? A 0.5s B 1.0s C 1.4s D 2.0s

D

A crane lifts a shipping crate that weighs 5000 N at a constant speed of 4 m/s. At what rate is this crane doing work on the crate? A 2000 W B 4000 W C 10000 W D 20000 W

D

A person is pulling a block of mass m with a force equal to its weight directed 30 degrees above the horizontal plane across a rough surface, generating a friction f on the block. If the person is now pushing downers on the block with the same force 30 degrees above the horizontal plane across the same rough surface, what is the friction on the block? A f B 1.5f C 2f D 3f

D

A rectangular book weighing 20 N with sides of 10 cm and 20 cm is placed on the horizontal table. Using each of your hands, you exert forces of 10 N each in opposite directions at opposite corners such that you are pushing parallel to the shorter side in each case. What net torque are you providing the book? A 0 B 0.5 C 1 D 2

D

A satellite weighs 10^4 N at ground control. What best approximates the acceleration it experiences in orbit at an altitude of twice the earths radius? A 111 B 2.5 C 2 D 1.1

D

A tube with one end closed and one end open resonates for a wave with wavelength lamda a as shown. The next shorter wavelength at which resonance will occur is lamda b. The ratio of these two wavelengths is A 1/4 B 1/3 C 3/5 D 5/3

D

An electric dipole consists of a pair of equal but opposite point charges of magnitude 4.0 nC separated by a distance of 2.0 m. What is the electric field strength at the point midway between the charges? A 0 B 9.0 x 10^4 C 1.8 x 10^5 D 7.2 x 10^5

D

An elevator has a mass of 500 kg. it may safely carry an additional mass of 1000 kg and accelerate upward at 2 m/s^2. What is the tension in the cable under these maximum conditions? A 4900 N B 9800 N C 14700 N D 18000 N

D

An object has a kinetic energy of K. If the speed of the object were doubled what would be the resulting kinetic energy? A 1/2 K B K C 2 K D 4K

D

An object is thrown with an initial speed of 7 m/s directed 45 degrees above the horizontal from a cliff. After reaching the peak of the trajectory, it falls 20 m to the ground below. What is the approximate ratio of the time it takes to hit the ground from the peak of the trajectory to the time it takes from its release to the peak of the trajectory. A 0.5 B 1 C 2 D 4

D

An object of mass 3 kg is undergoing uniform circular motion. The objects speed is 4 m/s and the radius of the path is 0.5m. How much work is done on this object by the centripetal force? A 50 j B 12 j C 6 j D 0 j

D

An object of mass 5 kg is acted upon by exactly four forces, each of magnitude 10 N. Which of the following could NOT be the resulting acceleration of the object? A 0 B 4 C 8 D 10

D

At a distance of 20 m from a source of sound, the sound level is 40 dB. If the observer backs up to a distance of 40 m from the source, what will the sound level be? Assume no absorption not reflection of sound. A 14 dB B 20 dB C 28 dB D 34 dB

D

Determine the total power dissipated through the circuit shown above in terms of V, r1 r2 and r3, A v^2/(r1+r2+r3) B (r1+r2+r3)/V^2 C r1(r2+r3)/v^2(r1+r2+r3) D v^2(r1+r2+r3)/r1(r2+r3)

D

If L, M and T denote the dimensions of length, mass and time respectively, what are the dimensions of power? A L^2M/T^2 B M^2L/T^2 C L^2M/T^3 D ML^2/T^3

D

If a charge of +q is placed at point P, the electric field at point P would A increase by 1/3 B increase by 1/2 C decrease by 1/3 D remain the same

D

If the rod in the figure above is uniform and has a mass m, what is the tension in the supporting string? The rod is free to rotate about point P. A 1/2 mg sin theta B mg sin theta C 1/2 mg cos theta D 1/2 mg

D

The spring of force constant 800 N/m is hung from a ceiling. A block of mass 4.0 kg is hung from its lower end and allowed to come to a rest. How far will the block stretch the spring? A 0.50 cm B 1.0 cm C 3.2 cm D 5.0 cm

D

Two charges are placed as shown at the vertices of an equilateral triangle. What is he direction of the electric field at point P? A a B b C c D d

D

Two people, one of mass 100 kg and the other of mass 50 kg, stand facing each other on an ice covered (essentially frictionless) pond. If the heavier person pushes on the lighter one with a force F, then A the force felt by the heavier person is -1/2F B the force felt by the person is -2F C the magnitude of the acceleration of the lighter person will be half of the magnitude of the acceleration of the heavier person D the magnitude of the acceleration of the lighter person will be twice the magnitude of the acceleration of the heavier person

D

What happens to the force of gravitational attraction between two small objects if the mass of each object is doubled and the distance between their centers is doubled? A it is doubled B it is quadrupled C it is halved D it remains the same

D

What is maximum velocity of the mass? A 0.4 B 0.8 C 1.41 D 2

D

What is the power developed by the force? A FR B Fv C Mv^2 D 0

D

Wheatstone bridge (diagram above) is a configuration of resistors and a sensitive current meter called a galvanometer that is used to determine the resistance of an unknown resistor. In the Wheatstone building shown here, find the value of Rx such that the current through galvanometer G is 0. A 25 B 15 C 10 D 2.5

D

Which of the following concerning uniform circular motion is true? A the centrifugal force is the action reaction pair B the centripetal acceleration and velocity point in the same direction C the velocity of the object in motion changes whereas the acceleration of the object is constant D a satellite undergoing uniform circular motion is falling toward the center in a circular path

D

Which of the following relates Pb, the rate at which energy is dissipated by resistor b, and Pe, the rate at which the energy is dissipated by resistor e? A Pb = 3 Pe B Pb = 9 Pe C Pe = 3 Pb D Pe = 9 Pb

D

You are standing on a railroad track as a train approaches at a constant velocity. Suddenly the engineer sees you applies the brakes and sounds the whistle. Which of the following describes the sound of the whistle as you hear it starting from that moment? A loudness increasing pitch increasing B loudness increasing pitch constant C loudness decreasing pitch increasing D loudness increasing pitch decreasing

D