final exam

A string of length L, mass per unit length m, and tension T is vibrating at its fundamental frequency. If the mass per unit length is doubled, with all other factors held constant, what is the effect on the fundamental frequency? A. It becomes 1/√2 times as large. B. It becomes √2 times larger. C. It is unchanged. D. It becomes 2 times larger. E. It becomes one-half as large.

A. It becomes 1/√2 times as large.

A woman runs up a flight of stairs. The gain in her gravitational potential energy is U. If she runs up the same stairs with twice the speed, what is her gain in potential energy? A. U B. 2U C. ½U D. 4U E. ¼U

A. U

If you extend a spring twice than before, the energy stored in the spring will be A. four times greater. B. two times greater. C. four times smaller. D. two times smaller E. unchanged.

A. four times greater.

A 5-kg object slides down a frictionless surface inclined at an angle of 30º from the horizontal. The total distance moved by the object along the plane is 10 meters. The work done on the object by the normal force of the surface is A. zero B.0.50 kJ C.0.43 kJ D.0.58 kJ E.0.25 kJ

A. zero

An object of mass 3 kg is moving with 2 m/s in the positive x-direction. Another object B of mass 1 kg is moving in the negative x-direction with the same speed, 2 m/s. If they collide on the way and form a single system, find the final velocity of the combined system. A.1 m/s B.2 m/s C.3 m/s D.2.5 m/s E.1.5 m/s

A.1 m/s

A new roller coaster contains a loop-the-loop in which the car and rider are completely upside down. If the radius of the loop is 16.4 m with what minimum speed must the car traverse the loop so that the rider does not fall out while upside down at the top? Assume the rider is not strapped to the car. A.12.7 m/s B.10.1 m/s C.14 m/s D.14.9 m/s

A.12.7 m/s

A woman uses a pulley and a rope to raise a 16 kg weight to a height of 3 m. If it takes 4 s to do this, about how much power is she supplying? A.120 W B.220 W C.320 W D.420 W

A.120 W

A flute has a length of 58 cm. If the speed of sound in air is 343 m/s, what is the fundamental frequency of the flute, assuming it is a tube closed at one end and open at the other? A.148 Hz B.296 Hz C.444 Hz D.591 Hz E.none of those answers

A.148 Hz

A flywheel of rotational inertia 8 kgm2 is rotating with a uniform angular speed of 7 rad/s. Calculate is rotational kinetic energy. A.196 J B.125 J C.75 J D.524 J E.25 J

A.196 J

The density of aluminum is about 2.70 g/cm3. In SI units, this is equal to A.2.70 x 10^3 kg/m^3. B.2.70 kg/m^3 C.2.70 x 10^2 kg/m^3. D.2.70 x 10^6 kg/m^3. E.2.70 x 10^5 kg/m^3.

A.2.70 x 10^3 kg/m^3.

A uniform bar has two small balls glued to its ends. The bar is 2.30 m long and with mass 4.00 kg , while the balls each have mass 0.400 kg and can be treated as point masses. Find the moment of inertia of this combination about an axis perpendicular to the bar through its center. A.2.82 kg⋅m2 B.5.56 kg⋅m2 C.1.76 kg⋅m2 D.1.06 kg⋅m2 E.8.44 kg⋅m2

A.2.82 kg⋅m2

A 1400-kg car enters a passing zone and accelerates from 70 km/h to 95 km/h. How much work is done on the car? A.220,000 J B.315,000 J C.125,045 J D.280,300 J E.260,000 J

A.220,000 J

A skier starts from rest at the top of a 24° slope 1.3 km long. Neglecting friction, how long does it take to reach the bottom? A.26 s B.16 s C.36 s D.40 s E.12 s

A.26 s

A physics book slides off a horizontal tabletop with a speed of 1.70 m/s. It strikes the floor in 0.350 s. Ignore air resistance. Find the magnitude of book's velocity, just before the book reaches the floor. A.3.83 m/s B.3.33 m/s C.1.70 m/s D.0.553 m/s

A.3.83 m/s

A pendulum consists of a 2.3-kg bob attached to a light 2.5-m-long string. While hanging at rest with the string vertical, the bob is struck a sharp horizontal blow, giving it a horizontal velocity of 4.9 m/s. At the instant the string makes an angle of 22° with the vertical, calculate the gravitational potential energy relative to its value at the lowest point. A.4.1 J B.56.4 J C.23.4 J D.32.5 J E.40.6 J

A.4.1 J

A flock of geese is attempting to migrate due south, but the wind is blowing from the west at 5.1 m/s. If the birds can fly at 7.5 m/s relative to the air, what direction should they head? A.43° B.47° C.34° D.22°

A.43°

A jetliner touches down at 270 km/h. The plane then decelerates at 4.5 m/s2. What's the minimum runway length on which this aircraft can land? A.625 m B.450 m C.855 m D.525 m E.375 m

A.625 m

A box of mass 68 kg is at rest on a horizontal frictionless surface. A constant horizontal force F then acts on the box and accelerates it to the right. It is observed that it takes the box 3.9 seconds to travel 98 meters. What is the magnitude of the force? A.880 N B.650 N C.345 N D.575 N E.730 N

A.880 N

A 70.0 kg archer, standing on frictionless ice, shoots a 80.0 g arrow at a speed of 80 m/s. What is the recoil speed of the archer ? A.9.1×10−2 m/s B.1.1×10−2 m/s C.7.3×10−2 m/s D.3.5×10−2 m/s E.23.4×10−2 m/s

A.9.1×10−2 m/s

Two uniform solid spheres of the same size, but different mass, are released from rest simultaneously at the same height on a hill and roll to the bottom without slipping. Which of the following statements about these spheres is true? A.Both spheres arrive at the bottom with the same forward speed. B.Both spheres arrive at the bottom with the same total kinetic energy. C.The heavier sphere reaches the bottom ahead of the lighter one. D.The lighter sphere reaches the bottom ahead of the heavier one.

A.Both spheres arrive at the bottom with the same forward speed.

A 620-g object traveling at 2.1 m/s collides head-on with a 320-g object traveling in the opposite direction at 3.8 m/s. If the collision is perfectly elastic, what is the change in the kinetic energy of the 620-g object? A.It loses 0.23 J. B.It loses 1.4 J. C.It gains 0.69 J. D.It loses 0.47 J. E.It doesn't lose any kinetic energy because the collision is elastic.

A.It loses 0.23 J.

A satellite orbits the Earth in uniform circular motion. What is the direction of centripetal acceleration of the satellite? A.The centripetal acceleration vector points radially inward toward the Earth. B.The centripetal acceleration vector points in the direction of the satellite's velocity. C.The centripetal acceleration vector points in the direction opposite that of the satellite's velocity. D.The centripetal acceleration vector points radially outward from the Earth. E.Because the centripetal acceleration is a scalar quantity, it doesn't have a direction.

A.The centripetal acceleration vector points radially inward toward the Earth.

For the same force, why does a long cannon impart more speed to a cannonball than a short cannon? A.The force is applied for a longer time in the long cannon. B.The force is applied for a shorter time in the long cannon. C.The force is applied for a longer time in the short cannon. D.The force per unit time is greater for a long cannon.

A.The force is applied for a longer time in the long cannon.

A mosquito runs head-on into a truck. Splat! Which is true during the collision? A.The mosquito exerts the same force on the truck as the truck exerts on the mosquito. B.The mosquito exerts a force on the truck but the truck does not exert a force on the mosquito. C.The mosquito exerts more force on the truck than the truck exerts on the mosquito. D.The truck exerts more force on the mosquito than the mosquito exerts on the truck. E.The truck exerts a force on the mosquito but the mosquito does not exert a force on the truck.

A.The mosquito exerts the same force on the truck as the truck exerts on the mosquito.

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.her hand is made to bounce from the bricks.

When an object is in uniform circular motion, A.only the direction of acceleration keeps changing. B.both magnitude and direction of acceleration keep changing. C.the net force is zero. D.neither magnitude nor direction of acceleration change.

A.only the direction of acceleration keeps changing.

Two balls are dropped at the same time from different heights. As they accelerate toward the ground, the distance between them will ? A.remain constant B.decrease C.increase D.be zero

A.remain constant

A rock of mass m is dropped to the ground from a height h. A second rock, with mass 7m, is dropped from the same height. When the second rock strikes the ground, which of the following best describes its kinetic energy? A.seven times that of the first rock B.the same as that of the first rock C.forty-nine times that of the first rock D.one-seventh as much as that of the first rock E.impossible to determine

A.seven times that of the first rock

The total mechanical energy of a system remains unchanged if A.there are no external forces acting on the system. B.some of the external forces acting on the system are conservative. C.the potential energy is constant. D.the external forces acting on the system are nonconservative. E.the kinetic energy is constant.

A.there are no external forces acting on the system.

A boulder following a straight-line path at constant velocity has A.zero acceleration. B.no forces acting on it. C.a net force acting upon it in the direction of motion. D.none of the above

A.zero acceleration.

A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is A.zero. B.down the hill and greater than the weight of the car. C.up the hill and greater than the weight of the car. D.up the hill and equal to the weight of the car. E.down the hill and equal to the weight of the car.

A.zero.

A 4.0-kg block starts from rest and slides 5.0 m down a plane inclined at 60º to the horizontal. The coefficient of kinetic friction between the surface and the block is 0.20. The work done by friction on the block is A. 98.0 J B 19.6 J C. 3.92 J D. 3.40 J E. 64. 0 J

B 19.6 J

The apparent weight of a fish in an elevator is greatest when the elevator A. moves downward at constant velocity. B. accelerates upward. C. moves upward at constant velocity. D. accelerates downward. E. is not moving.

B. accelerates upward.

If the kinetic energy of an object remains constant, the net work done on the object, A. is negative B. is zero. C. is positive. D. cannot be found without knowing mass, initial and final velocities.

B. is zero.

If you push twice as hard against a stationary wall, the amount of work you do on the wall A. remains constant but non-zero. B. remains constant at zero. C. doubles. D. quadruples. E. is halved.

B. remains constant at zero.

An object of mass 315 g is rotating about an axis with some angular speed. If its distance is 75 cm from the axis of rotation. What is its rotational inertia? A.5.5 kg.m2 B.0.18 kg.m2 C.0.45 kg.m2 D.2.4 kg.m2 E.1.5 kg.m2

B.0.18 kg.m2

What is 0.5342/3, to the proper number of significant figures? A.0.6582 B.0.658 C.0.7 D.0.66 E.none of the above

B.0.658

Two uniform solid spheres of the same size, but different mass, are released from rest simultaneously at the same height on a hill and roll to the bottom without slipping. Which of the following statements about these spheres are true? 1.Both spheres reach the bottom at the same time. 2.The heavier sphere reaches the bottom ahead of the lighter one. 3.Both spheres arrive at the bottom with the same forward speed. 4.Both spheres arrive at the bottom with the same total kinetic energy. A.1 B.1, 3 C.2, 3 D.2, 4 E.4

B.1, 3

A highway curve with radius 900 ft is to be banked so that a car travelling 55 mi/h will not skid sideways even in the absence of friction. At what angle should the curve be banked? (1 foot = 0.3048 m, 1 mile = 1609 m, 1 h= 3600 s) A.18.2° B.12.7° C.8.7° D.6.3° E.15.3°

B.12.7°

The crankshaft in a race car goes from rest to 3540 rpm in 2.3 s . What is the crankshaft's angular acceleration? A.65 rad/s2 B.160 rad/s2 C.96 rad/s2 D.16 rad/s2 E.112 rad/s2

B.160 rad/s2

You slide a W = 900-N table across the kitchen floor by pushing with a force of 170 N . If the table moves at a constant speed, the friction force with the floor must be A.more than 900 N B.170 N C.more than 170 N D.900 N

B.170 N

A spring stretches by 21.0 cm when a 135 N object is attached. What is the weight of a fish that would stretch the spring by 35.4 cm? A.80.0 N B.228 N C.154 N D.319 N

B.228 N

A 5.0 kg dog sits on the floor of an elevator that is accelerating downward at 1.20 m/s2. What is the magnitude of the normal force of the elevator floor on the dog? A.55 N B.43 N C.49 N D.74 N E.34 N

B.43 N

A car is traveling in uniform circular motion on a section of flat roadway whose radius is r. The road is slippery, and the car is just on the verge of sliding off the roadway. If the car's speed were now doubled, what would be the smallest radius of the curve it could drive on without slipping? A.r/2 B.4r C.r/4 D.r E.2r

B.4r

A 2-kg object is moving in a plane, with its x and y coordinates given by x = 5t2 − 9t -2 and y = 3t3 +7t+2, where x and y are in meters and t is in seconds. Find the magnitude of the net force acting on this object at t = 1.5 s. A.78.3 N B.57.6 N C.84.3 N D.45.6 N E.126.6 N

B.57.6 N

Movers slide a 73-kg file cabinet along a floor where the coefficient of kinetic friction is 0.81. What's the frictional force on the cabinet? A.715 N B.580 N C.872 N D.632 N E.480 N

B.580 N

A football is kicked at an angle of 45∘ with a speed of 26 m/s. If it stays in air for 3.75 s before it hits the ground, how far does it go? A.79 m B.69 m C.59 m D.110 m

B.69 m

Why does bending your legs when running enable you to swing your legs to and fro more rapidly? A.Bending your legs puts the rotational axis in the center of the leg, thus reducing rotational inertia. B.Bending your legs shortens them, thus reducing rotational inertia. C.Bending your legs decreases the angular speed, thus reducing rotational inertia. D.Bending your legs increases the height of the foot, thus reducing rotational inertia.

B.Bending your legs shortens them, thus reducing rotational inertia.

Which requires more work: lifting a 50-kg sack a vertical distance of 2 m or lifting a 25-kg sack a vertical distance of 4 m? A.The sack lifted 4 m requires more work. B.Both take the same 1000 J. C.The 50 kg sack requires more work. D.The 25 kg sack requires more work.

B.Both take the same 1000 J.

Rachel is pushing a box across the floor while Jon, at the same time, is hoping to stop the box by pushing in the opposite direction. There is friction between the box and floor. If the box is moving at constant speed, then the magnitude of Rachel's pushing force is A.Equal to the magnitude of Jon's force. B.Greater than the magnitude of Jon's force. C.Less than the magnitude of Jon's force. D.The problem can't be answered without knowing how large the friction force is.

B.Greater than the magnitude of Jon's force.

When is the total momentum of a system conserved? A.Always. B.If the system is isolated. C.If the forces are conservative. D.Never; it's just an approximation.

B.If the system is isolated.

A ball of clay falls freely to the hard floor. It does not bounce noticeably, and it very quickly comes to rest. What then has happened to the energy the ball had while it was falling? A.Most of it went into sound. B.It is in the ball and floor (and walls) as energy of invisible molecular motion. C.It has been transferred into the ball by heat. D.It has been used up in producing the downward motion. E.It has been transformed back into potential energy.

B.It is in the ball and floor (and walls) as energy of invisible molecular motion.

A bicycle racer is traveling at constant speed v around a circular track. The centripetal acceleration of the bicycle is ac. What happens to the centripetal acceleration of the bicycle if the speed is doubled to 2v? A.The centripetal acceleration does not change. B.The centripetal acceleration increases to 4ac. C.The centripetal acceleration increases to 2ac. D.The centripetal acceleration decreases to 0.25 ac. E.The centripetal acceleration decreases to 0.5ac.

B.The centripetal acceleration increases to 4ac.

Which has a greater momentum: a heavy truck at rest or a moving skateboard? A.Both have zero momentum. B.The moving skateboard. C.Both have the same momentum. D.The heavy truck at rest.

B.The moving skateboard.

The linear momentum and velocity A.are always perpendicular to each other. B.are always parallel to each other. C.are independent to each other D.have opposite directions.

B.are always parallel to each other.

A passenger on a Ferris wheel moves in a vertical circle. at the top of the Ferris wheel, the upward force the seat applies to the passenger is A.greater than passenger's weight. B.is less than passenger's weight C.equal to passenger's weight. D.equal to zero.

B.is less than passenger's weight

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction? A.momentum only. B.momentum and mechanical energy. C.momentum and potential energy. D.kinetic energy only. E.momentum and kinetic energy.

B.momentum and mechanical energy.

A ball is tossed straight up in the air. At its very highest point, the ball's instantaneous acceleration ay is A.zero. B.negative. C.positive. D.unknown.

B.negative.

When two vehicles collide, momentum is conserved _______. A.if the collision is elastic B.whether the collision is elastic or inelastic. C.if the collision is inelastic. D.only if deformation of either vehicle does not occur.

B.whether the collision is elastic or inelastic.

A pipe open at both ends resonates at a fundamental frequency fopen. When one end is covered and the pipe is again made to resonate, the fundamental frequency is fclosed. Which of the following expressions describes how these two resonant frequencies compare? A. 〖 f〗_closed= f_open B. f_closed= 2f_open C. f_closed= 1/2 f_open D.f_closed= 3/2 f_open E.f_closed=4f_open

C. f_closed= 1/2 f_open

How far would you have to stretch a spring with k = 1.4 kN/m for it to store 210 J of energy? A.0.45 m B.0.34 m C.0.54 m D.0.26 m E.0.64 m

C.0.54 m

A 5.0 kg block has an acceleration of 0.20 m/s2 when a force is exerted on it. A second block has an acceleration of 0.10 m/s2 when subject to the same force. What is the mass of the second block? A.7.5 kg B.2.5 kg C.10 kg D.5.0 kg

C.10 kg

A 15 kg box slides down a long, frictionless incline of angle 30°. It starts from rest at time t = 0 at the top of the incline at a height of 17 m above ground. What is the speed of the box just as it reaches the bottom of the incline. A.42.4 m/s B.34.2 m/s C.18.3 m/s D.26.1 m/s E.6.4 m/s

C.18.3 m/s

Two forces act on a 29-kg object. One force has magnitude 65 N directed 59° clockwise from the positive x-axis, and the other has a magnitude 35 N at 32° clockwise from the positive y-axis. What is the magnitude of this object's acceleration? A.3.1 m/s2 B.2.7 m/s2 C.2.0 m/s2 D.2.3 m/s2 E.4.2 m/s2

C.2.0 m/s2

A motor is lifting a mass of 35.0 kg at a constant speed of 6.00 m/s. If friction is neglected, the power developed by the motor to do this lifting is A.740 W B.1.5 x 10^3 W C.2.1 x 10^3 W D. 59 W E.43 W

C.2.1 x 10^3 W

At t=0 a cooling fan running at 200 rad/s is turned off and then slows down at a rate of 15 rad/s2 . Simultaneously (at t=0) a second cooling fan is turned on and begins to spin from rest with an acceleration of 60 rad/s2. Find the time at which both fans have the same angular speed. A.3.8 s B.1.2 s C.2.7 s D.5.6 s E.12.3 s

C.2.7 s

A car is moving at 65 mi/h. Express its speed in m/s [ 1 mile = 1609 m A.26 B.15 C.29 D.16 E.21

C.29

A football is kicked at an angle of 40∘ with a speed of 26 m/s. To the nearest second, how long will the ball stay in the air? A.4.4 s B.4.5 s C.3.4 s D.4.9 s

C.3.4 s

A car drives horizontally off a 75 m -high cliff at a speed of 28 m/s . Ignore air resistance. How long will it take the car to hit the ground? A.4.2 s B.4.3 s C.3.9 s D.2.5 s E.6.1 s

C.3.9 s

A block slides down a smooth ramp, starting from rest at a height h. When it reaches the bottom it's moving at speed v. It then continues to slide up a second smooth ramp. At what height is its speed equal to v/2? A.h/4 B.h/2 C.3h/4 D.2h

C.3h/4

At time t = 0 s, a wheel has an angular displacement of zero radians and an angular velocity of +26 rad/s. The wheel has a constant acceleration of -0.5 rad/s2. In this situation, the time t, at which the wheel comes to a mandatory halt, is closest to: A.110 s B.74 s C.52 s D.91 s E.130 s

C.52 s

The kinetic energy of an object of mass 2 kg is 16 J. What is its linear momentum? A.4 kg.m/s B.2 kg.m/s C.8 kg.m/s D.16 kg.m/s E.32 kg.m/s

C.8 kg.m/s

You and a friend each carry a 15 kg suitcase up two flights of stairs, walking at a constant speed. Take each suitcase to be the system. Suppose you carry your suitcase up the stairs in 30 s while your friend takes 60 s . A.You did more work, but both of you expended the same power. B.You did more work and expended more power. C.Both of you did the same work, but you expended more power. D.Both of you did the same work, but you expended less power.

C.Both of you did the same work, but you expended more power.

As distance increases between most of the mass of an object and its center of rotation, how does rotational inertia change? A.It decreases. B.It stays the same. C.It increases. D.It goes to zero.

C.It increases.

An archer shoots an arrow horizontally from the center of the string of a bow held vertically. After the arrow leaves it, the string of the bow will vibrate as a superposition of what standing-wave harmonics? A.None; it vibrates as a traveling wave rather than a standing wave. B.It vibrates only in the even-numbered harmonics 2, 4, 6, 8, . . . . C.It vibrates only in the odd-numbered harmonics 1, 3, 5, 7, . . . . D.It vibrates in all harmonics. E.It vibrates only in the second harmonic.

C.It vibrates only in the odd-numbered harmonics 1, 3, 5, 7, . . . .

A car is raised a certain distance in a service-station lift, thus giving it potential energy relative to the floor. If it were raised twice as high, how much more potential energy would it have? A.It would have half as much potential energy. B.It would have the exact same potential energy. C.It would have twice as much potential energy. D.It would have equal and opposite potential energy.

C.It would have twice as much potential energy.

How is a flywheel constructed to maximize its rotational inertia? A.Most of the mass is concentrated near the axis. B.The mass is uniformly distributed across the radius of the disk. C.Most of the mass is concentrated far from the axis. D.Most of the mass is concentrated near a ring half way between the axis and the rim.

C.Most of the mass is concentrated far from the axis.

A frog leaps vertically into the air and encounters no appreciable air resistance. Which statement about the frog's motion is correct? A.On the way up its acceleration is 9.8m/s2 upward, and on the way down its acceleration is 9.8m/s2 downward. B.On the way up and on the way down its acceleration is 9.8m/s2 downward, and at the highest point its acceleration is zero. C.On the way up, on the way down, and at the highest point its acceleration is 9.8m/s2 downward. D.At the highest point, it reverses the direction of its acceleration.

C.On the way up, on the way down, and at the highest point its acceleration is 9.8m/s2 downward.

Susana ascends a mountain via a short, steep trail. Sean ascends the same mountain via a long, gentle trail. Which of the following statements is true? A.Susana gains more gravitational potential energy than Sean. B.Susana gains less gravitational potential energy than Sean. C.Susana gains the same gravitational potential energy as Sean. D.To compare energies, we must know the height of the mountain. E.To compare energies, we must know the lengths of the two trails.

C.Susana gains the same gravitational potential energy as Sean.

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force? A.Hitting the other car B.Hitting the brick wall C.The force would be the same in both cases. D.We cannot answer this question without more information. E.None of these is true.

C.The force would be the same in both cases.

The slope at a point on a position-versus-time graph of an object is A.The distance traveled by the object to that point. B.The object's acceleration at that point. C.The object's velocity at that point. D.The object's speed at that point. E.None of the above.

C.The object's velocity at that point.

A stone is tied to a string and swung along the path of a vertical circle at constant speed. When is the string most likely to break? A.The string is equally likely to break for any position of the stone. B.When the stone is at the very top of the circle. C.When the stone is at the very bottom of the circle. D.When the string is horizontal.

C.When the stone is at the very bottom of the circle.

The total momentum of a system is conserved whenever A.a constant external force acts on the system. B.the system is accelerating. C.a net external force is zero. D.the system is decelerating. it is not moving

C.a net external force is zero.

Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom A.after the small block. B.before the small block. C.at the same time as the small block.

C.at the same time as the small block.

To decompose a vector means to A.break it into several smaller vectors. B.break it apart into scalars. C.break it into pieces parallel to the axes. D.place it at the origin.

C.break it into pieces parallel to the axes.

To impart the greatest momentum to an object, you must A.exert a force over the greatest time. B.exert the greatest force over the shortest time. C.exert the greatest force over the longest time. D.exert the greatest force.

C.exert the greatest force over the longest time.

A brick is resting on a rough incline as shown in the figure. The friction force acting on the brick, along the incline, is A.greater than the weight of the brick. B.zero. C.less than the weight of the brick. D.equal to the weight of the brick.

C.less than the weight of the brick.

You throw a ball horizontally off a roof. Assuming the ball behaves as an ideal projectile, the time until it lands is determined only by A.its initial speed and the horizontal distance to the point where it lands. B.the height of the roof and its initial speed. C.the height of the roof.

C.the height of the roof.

The maximum speed at which a car can safely negotiate a frictionless banked curve depends on all of the following except A.the diameter of the curve. B.the acceleration due to gravity. C.the mass of the car. D.the radius of the curve. E.the angle of banking.

C.the mass of the car.

Suppose all six equal-length strings of an acoustic guitar are played without fingering, that is, without being pressed down at any frets. What quantities are the same for all six strings? A. the fundamental wavelength of the sound emitted. B.the fundamental frequency. C.the speed of the sound emitted. D.the speed of the string wave. E.None of above is correct

C.the speed of the sound emitted.

The law of conservation of energy is a statement that A.energy must be conserved and you are breaking a law if you waste energy. B.the supply of energy is limited so we must conserve. C.the total amount of energy is constant. D.energy cannot be used faster than it is created.

C.the total amount of energy is constant.

A car drives horizontally off a 75 m -high cliff at a speed of 28 m/s . Ignore air resistance. How far from the base of the cliff will the car hit? A.210 m B.200 m C.220 m D.110 m E.240 m

D.110 m

A turntable that spins at a constant 79 rpm takes 3.6 s to reach this angular speed after it is turned on. Find its angular acceleration (in rad/s2), assuming it to be constant. A.12.3 rad/s2 B.8.3 rad/s2 C.0.3 rad/s2 D.2.3 rad/s2

D.2.3 rad/s2

An arrow fired horizontally at 8 m/s travels 16 m horizontally. From what height was it fired? A.12 m B.8 m C.16 m D.20 m

D.20 m

1.0 m/s is how many km/h ? A.4.6 B.5.3 C.8.4 D.3.6 E.2.5

D.3.6

If the contraction of left ventricle of the heart lasts 250 ms and the rate of flow of the blood in the aorta is 1.0 m/s, what is the average acceleration of a red blood cell as it leaves the heart? A.250 m/s2 B.25 m/s2 C.40 m/s2 D.4.0 m/s2 E. 85 m/s2

D.4.0 m/s2

A 2.3-kg object traveling at 6.1 m/s collides head-on with a 3.5-kg object traveling in the opposite direction at 4.8 m/s. If the collision is perfectly elastic, what is the final speed of the 2.3-kg object? A.4.3 m/s B.0.48 m/s C.6.6 m/s D.7.1 m/s E.3.8 m/s

D.7.1 m/s

A 60.0-kg person rides in elevator while standing on a scale. The elevator is traveling downward but slowing down at a rate of 2.00 m/s2. The reading on the scale is closest to A.349 N. B.589 N. C.120 N. D.708 N. E.469 N.

D.708 N.

A car is traveling at 24 m/s . The driver applies the brakes and the car decelerates at - 4.0 m/s2 . What is the stopping distance? A.4.0 m B.97 m C.82 m D.72 m E.34 m

D.72 m

You walk 49 m to the north, then turn 60° to your right (from north) and walk another 45 m. How far are you from where you originally started? A.43 m B.47 m C.88 m D.81 m E.78 m

D.81 m

Initially a body moves in one direction and has kinetic energy K. Then it moves in the opposite direction with three times its initial speed. What is the kinetic energy now? A.K B.3 K C.- 3K D.9 K E.- 9 K

D.9 K

The gas pedal in a car is sometimes referred to as "the accelerator." Which other controls on the vehicle can be used to produce acceleration? A.The brakes B.The steering wheel C.The gear shift D.All of the above

D.All of the above

On a merry-go-round, you decide to put your toddler on an animal that will have maximum angular velocity. Which animal do you pick? A.one close to the hub. B.one close to the rim. C.one in between the hub and the rim. D.Any animal; they all have the same angular velocity.

D.Any animal; they all have the same angular velocity.

Tennis balls experience a large drag force. A tennis ball is hit so that it goes up and then comes back straight down. The direction of the drag force is A.Always up. B.Up and then down. C.Always down. D.Down and then up.

D.Down and then up.

Which of the following statements is NOT correct? A.The work done by a conservative force on an object is independent on the path taken. B.The work done by a conservative force on an object along path A®B is negative that of path B®A. C.The force due to gravity is an example of a conservative force. D.Friction is an example of a conservative force. E.The work done by friction on an object can depend on the path taken.

D.Friction is an example of a conservative force.

A person is pushing horizontally on a box with a constant force, causing it to slide across the floor with a constant speed. When he stops pushing the box, it A.Immediately comes to a stop. B.Continues moving at a constant speed for a while, then gradually slows down to a stop. C.Immediately changes to a slower but constant speed. D.Immediately begins slowing down and eventually stop.

D.Immediately begins slowing down and eventually stop.

An object is rotating about an axis. If you halve the distance of the object from the axis of rotation, how would the moment of inertia change? A.It remains same. B.It would increase by a factor of 2 C.It would decrease by a factor of 2 D.It would decrease by a factor of 4 E.It would increase by a factor of 4.

D.It would decrease by a factor of 4

Which of the following statements is true? A.The kinetic and potential energies of an object must always be positive quantities. B.The kinetic and potential energies of an object must always be negative quantities. C.Kinetic energy can be negative but potential energy cannot. D.Potential energy can be negative but kinetic energy cannot. E.None of these statements is true.

D.Potential energy can be negative but kinetic energy cannot.

Displacement can be obtained from: A.The slope of an acceleration-time graph B.The slope of a velocity-time graph C.The area under an acceleration-time graph D.The area under a velocity-time graph The slope of an acceleration-time graph

D.The area under a velocity-time graph

An apple hanging from a limb has potential energy because of its height. If it falls, what becomes of this energy just before it hits the ground? When it hits the ground? A.The energy is potential energy before it hits the ground; it is thermal energy after. B.The energy is thermal energy before it hits the ground; it is kinetic energy after. C.The energy is kinetic energy before it hits the ground; it is potential energy after. D.The energy is kinetic energy before it hits the ground; it is thermal energy after.

D.The energy is kinetic energy before it hits the ground; it is potential energy after.

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 4 N and 0 N, respectively. B.The net forces are 6 N and 10 N, respectively. C.The net forces are 14 N and 20 N, respectively. D.The net forces are 6 N and 0 N, respectively.

D.The net forces are 6 N and 0 N, respectively.

A motorcycle travels at a constant speed around a circular track. Which one of the following statements about this motorcycle is true? A.The motorcycle has a velocity vector that points along the radius of the circle. B.The motorcycle is characterized by a constant velocity vector. C.The motorcycle is characterized by a constant acceleration vector. D.The velocity of the motorcycle is changing. E.The motorcycle has an acceleration vector that is tangent to the circle at all times.

D.The velocity of the motorcycle is changing.

In an elastic collision, A.only kinetic energy is conserved. B.only momentum is conserved. C.neither momentum nor kinetic energy is conserved D.both momentum and kinetic energy are conserved E.forces involved are non-conservative.

D.both momentum and kinetic energy are conserved

An impulse can be increased by A.decreasing the force and decreasing the time interval. B.maintaining the force and decreasing the time interval. C.decreasing the force and maintaining time interval. D.increasing the force or increasing the time interval..

D.increasing the force or increasing the time interval..

The displacement of an object for a round trip between the two locations A.is always greater than zero. B.is always less than zero. C.is not zero. D.is zero. E.can have any value.

D.is zero.

The quantity that is called impulse can be measured by the _______. A.how long the force acts compared to the amount of time B.difference between force and time. C.addition of force and time. D.product of force and time.

D.product of force and time.

If you walk up a flight of stairs at constant speed, gaining vertical height h, the work done on you (the system, of mass m) is A.+mgh, by the normal force of the stairs. B.−mgh, by the normal force of the stairs. C.+mgh, by the gravitational force of the earth. D.−mgh, by the gravitational force of the earth.

D.−mgh, by the gravitational force of the earth.

A string of length L, mass per unit length m, and tension T is vibrating at its fundamental frequency. If the length of the string is doubled, with all other factors held constant, what is the effect on the fundamental frequency? A. It becomes two times larger. B. It becomes √2 times larger. C. It is unchanged. D. It becomes 1/√2 times as large. E. It becomes one-half as large.

E. It becomes one-half as large.

A 3.1 kg block of wood sits on a table. A 3.0 g bullet, fired horizontally at a speed of 460 m/s , goes completely through the block, emerging at a speed of 220 m/s. What is the speed of the block immediately after the bullet exits? A.1.63 m/s B.0.45 m/s C.0.67 m/s D.3.67 m/s E.0.23 m/s

E.0.23 m/s

A 1.5 m-long barbell of negligible mass consists of 50-kg & 80-kg weights at the opposite ends. Its center of mass from 50-kg mass is closest to, A.0.58 m B.1.5 m C.0.75 m D.3.0 m E.0.92 m

E.0.92 m

If you halve both mass and velocity of an object, its kinetic energy changes by a factor of A.½ B.¼ C.4 D.2 E.1/8

E.1/8

While standing in a low tunnel, you raise your arms and push against the ceiling with a force of 100 N . Your mass is 80 kg . What force does the ceiling exert on you? A.10 N B.980 N C.690 N D.790 N E.100 N

E.100 N

When a wheel turns through an angle 94.25 radians, the number of turns it has completed is closest to A.47 B.6 C.30 D.3 E.15

E.15

Which of the following correctly ranks the lengths from largest to smallest? A.1 mi, 1 km, 2000 m, 10^6 um B.1 km, 1 mi, 2000 m, 10^6 um c.2000 m, 10^6 um, 1 km, 1 mi D.1 mi, 2000 m, 1 km, 10^6 um E.2000 m, 1 mi, 1 km, 10^6 um

E.2000 m, 1 mi, 1 km, 10^6 um

The longest recorded pass in an NFL game traveled 80 yards in the air from the quarterback to the receiver. Assuming that the pass was thrown at the optimal 45∘ angle, what was the speed at which the ball left the quarterback's hand? [1 yard = 91.44 cm A.38 m/s B.13 m/s C.18 m/s D.58 m/s E.28 m/s

E.28 m/s

A stone is thrown upward at an angle of 48° above the horizontal. Its maximum height during the trajectory is 23 m. What was the stone's initial speed? A.12.4 m/s B.23.4 m/s C.34.2 m/s D.21.2 m/s E.28.6 m/s

E.28.6 m/s

A thin uniform bar has a moment of inertia I about an axis perpendicular to it through its center. If both the mass and length of this bar are doubled, its moment of inertia about the same axis will be A.I B.2I C.4I D.I/4 E.8I

E.8I

How many significant figures does the number 0109.020450 have? A.3 B.5 C.8 D.7 E.9

E.9

How much work can a 3.5-hp lawnmower engine do in 1hour? (1-hp = 746 W and 1 h = 3600 s) A.7.2x106 J B.12.4 x106 J C.3.4 x106 J D.5.3 x106 J E.9.4x106 J

E.9.4x106 J

A computer hard disk starts from rest, then speeds up with an angular acceleration of 190 rad/s2 until it reaches its final angular speed of 7200 rpm. How many revolutions has the disk made 10.0 s after it starts up? A.792 B.78 C.432 D.524 E.962

E.962

You slide a W = 900-N table across the kitchen floor by pushing with a force of 170 N . If the table moves at a constant acceleration, the friction force with the floor must be A.more than 900 N B.170 N C.more than 170 N D.900 N E.Less than 170 N

E.Less than 170 N

When two tuning forks are sounded at the same time, a beat frequency of 5 Hz occurs. If one of the tuning forks has a frequency of 245 Hz, what is the frequency of the other tuning fork? A. 247.5 Hz B.242.5 Hz C.240 Hz D.250 Hz E.More than one answer could be correct.

E.More than one answer could be correct.

A body moves with decreasing speed. Which of the following statements is true? A.The net work done on the body is positive, and the kinetic energy is increasing. B.The net work done on the body is positive, and the kinetic energy is decreasing. C.The net work done on the body is zero, and the kinetic energy is decreasing. D.The net work done on the body is negative, and the kinetic energy is increasing. E.The net work done on the body is negative, and the kinetic energy is decreasing.

E.The net work done on the body is negative, and the kinetic energy is decreasing.

Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined plane and allowed to slide down from rest A.It takes the lighter object 10 times longer to reach the bottom of the incline than the heavier object. B.It takes the heavier object 10 times longer to reach the bottom of the incline than the lighter object. C.It takes the lighter object 5 times longer to reach the bottom of the incline than the heavier object. D.It takes the heavier object 5 times longer to reach the bottom of the incline than the lighter object. E.The two objects reach the bottom of the incline at the same time.

E.The two objects reach the bottom of the incline at the same time.

A block has acceleration a when pulled by a string. If two identical blocks are glued together and pulled with twice the original force, what will their acceleration be? A.(1/4)a B.(1/2)a C.4a D.2a E.a

E.a

The reference point for gravitational potential energy A.must be at the initial position of the object. B.must be at the final position of the object. C.must be at ground level. D.must be at the lowest position ever reached by the object. E.can be chosen arbitrarily.

E.can be chosen arbitrarily.

A ball whirls on a string attached to a rotating peg in the center of frictionless table. If the string breaks suddenly, A.it keeps rotating with constant speed. B.it moves straight with increasing velocity. C.it moves straight with decreasing velocity. D.it keeps rotating with increasing speed. E.it moves straight with constant velocity.

E.it moves straight with constant velocity.

Which one of the following forces holds a car on a frictionless banked curve? A.the horizontal component of the car's weight B.the reaction force to the car's weight C.the vertical component of the normal force acting on the car D.the vertical component of the car's weight E.the horizontal component of the normal force acting on the car.

E.the horizontal component of the normal force acting on the car.

A block of mass m is dropped from the fourth floor of an office building and hits the sidewalk below at speed v. From what floor should the block be dropped to double that impact speed? A.the sixth floor B.the eighth floor C.the tenth floor D.the twelfth floor E.the sixteenth floor

E.the sixteenth floor

An object is undergoing uniform circular motion. Which of the following is/are true? I. The object is moving at constant velocity.II. The object is moving at constant speed.III. The object is accelerating. A.I and III B.III only C.I only D.II only E.I and II F.II and III

F.II and III