Physics LE 1

One revolution per minute is about:

0.105 rad/s

Three identical balls are tied by light strings to the same rod and rotate around it, as shown below. Rank the balls according to their rotational inertia, least to greatest.

1, 2, 3

The x and y coordinates in meters of the center of mass of the three-particle system shown below are:

1.4 m, 1.9 m

At the same instant that a 0.50-kg ball is dropped from 25 m above Earth, a second ball, with a mass of 0.25 kg, is thrown straight upward from Earth's surface with an initial speed of 15 m/s. They move along nearby lines and pass without colliding. At the end of 2.0 s the velocity of the center of mass of the two-ball system is:

15 m/s, down

A particle moves along the x axis. Its momentum is graphed below as a function of time. Rank the numbered regions according to the magnitude of the force acting on the particle, least to greatest.

2, 3, 4, 1

A wheel starts from rest and has an angular acceleration that is given by α(t) = (6.0 rad/s4)t2. The time it takes to make 10 rev is:

3.3 s

Blocks A and B are moving toward each other. A has a mass of 2.0 kg and a velocity of 50 m/s, while B has a mass of 4.0 kg and a velocity of -25 m/s. They suffer a completely inelastic collision. The kinetic energy lost during the collision is:

3750 J

A 1000-kg space probe is motionless in space. To start moving, its main engine is fired for 5 s during which time it ejects exhaust gases at 5000 m/s. At the end of this process it is moving at 20 m/s. The approximate mass of the ejected gas is:

4 kg

The figure shows a cylinder of radius 0.7 m rotating about its axis at 10 rad/s. The speed of the point P is:

7.0 m/s

A wheel initially has an angular velocity of 18 rad/s but it is slowing at a rate of 2.0 rad/s2. By the time it stops it will have turned through:

81 rad

Two uniform circular disks having the same mass and the same thickness are made from different materials. The disk with the smaller rotational inertia is: A. the one made from the more dense material B. the one made from the less dense material C. neither - both rotational inertias are the same D. the disk with the larger angular velocity E. the disk with the larger torque

A

Three identical balls are tied by light strings to the same rod and rotate around it, as shown below. Rank the balls according to their rotational inertia, least to greatest. A. 1,2,3 B. 3,2,1 C. 3,then1and2tie D. 1,3,2 E. All are the same

A (Ball farthest from rotation has highest inertia)

A disk starts from rest and rotates about a fixed axis, subject to a constant net torque. The work done by the torque during the second revolution is as the work done during the first revolution. A. the same B. twice as much C. half as much D. four times as much E. one-fourth as much

A, the same

The diagram shows a U-tube with cross-sectional area A and partially filled with oil of density ρ. A solid cylinder, which fits the tube tightly but can slide without friction, is placed in the right arm. The system is in equilibrium. The weight of the cylinder is: A. ALρg B. L3ρg C. Aρ(L+h)g D. Aρ(L−h)g E. none of these

A. ALρg

A meter stick on a horizontal frictionless table top is pivoted at the 80-cm mark. It is initially at rest. A horizontal force F1 is applied perpendicularly to the end of the stick at 0cm, as shown. A second horizontal force F2 (not shown) is applied at the 100-cm end of the stick. If the stick does not rotate: B. C. D. E. > |F1 | < |F1 | = |F1 | > |F1 | > |F1 | |F2 | |F2 | |F2 | |F2 | |F2 | ans: A 0cm 20cm 40cm 60cm 80cm 100cm for all orientations of F2 for all orientations of F2 for all orientations of F2 for some orientations of F2 and |F2 | < |F1 | for others for some orientations of F2 and |F2 | = |F1 | for others

A. F2 > F1

The angular velocity vector of a spinning body points out of the page. If the angular acceleration vector points into the page then: A. the body is slowing down B. the body is speeding up C. the body is starting to turn in the opposite direction D. the axis of rotation is changing orientation E. none of the above

A. Points into page = negative acceleration

Two balls have the same shape and size but one is denser than the other. If frictional forces are negligible when they are dropped in air, which has the greater acceleration? A. The heavier ball B. The lighter ball C. They have the same acceleration D. The heavier ball if atmospheric pressure is high, they lighter ball if it is low E. The lighter ball if atmospheric pressure is high, the heavier ball if it is low

A. The heavier ball

A car travels north at constant velocity. It goes over a piece of mud, which sticks to the tire. The initial acceleration of the mud, as it leaves the ground, is: vertically upward horizontally to the north horizontally to the south zero upward and forward at 45◦ to the horizontal

A. Vertically upward

A U-tube has dissimilar arms, one having twice the diameter of the other. It contains an incompressible fluid and is fitted with a sliding piston in each arm, with each piston in contact with the fluid. When an applied force does work W in pushing the piston in the narrow arm down, the fluid does work on the piston in the wide arm. A. W B. 2W C. W/2 D. 4W E. W/4

A. W

Bernoulli's equation can be derived from the conservation of:

A. energy

The apparent weight of a steel sphere immersed in various liquids is measured using a spring scale. The greatest reading is obtained for that liquid: A. having the smallest density B. having the largest density C. subject to the greatest atmospheric pressure D. having the greatest volume E. in which the sphere was submerged deepest

A. having the smallest density

A non-viscous incompressible liquid is flowing through a horizontal pipe of constant cross section. Bernoulli's equation and the equation of continuity predict that the drop in pressure along the pipe: A. is zero B. depends on the length of the pipe C. depends on the fluid velocity D. depends on the cross-sectional area of the pipe E. depends on the height of the pipe

A. is zero

A block is attached to each end of a rope that passes over a pulley suspended from the ceiling. The blocks do not have the same mass. If the rope does not slip on the pulley, then at any instant after the blocks start moving, the rope: A. pulls on both blocks, but exerts a greater force on the heavier block B. pulls on both blocks, but exerts a greater force on the lighter block C. pulls on both blocks and exerts the same magnitude force on both D. does not pull on either block E. pulls only on the lighter block

A. pulls on both blocks, but exerts a greater force on the heavier block

. A loaded ship passes from a lake (fresh water) to the ocean (saltwater). Saltwater is more dense than fresh water and as a result the ship will: A. ride higher in the water B. settle lower in the water C. ride at the same level in the water D. experience an increase in buoyant force E. experience a decrease in buoyant force

A. ride higher in the water

A person blows across the top of one arm of a U-tube partially filled with water. The water in that arm: A. rises slightly B. drops slightly C. remains at the same height D. rises if the blowing is soft but drops if it is hard E. rises if the blowing is hard but drops if it is soft

A. rises slightly

Consider a pipe containing a fluid, with the fluid being at rest. To apply Bernoulli's equation to this situation: A. set v equal to zero because there is no motion B. set g equal to zero because there is no acceleration C. set v and g both equal to zero D. set p equal to the atmospheric pressure E. cannot be done, Bernoulli's equation applies only to fluids in motion

A. set v equal to zero because there is no motion

For a wheel spinning on an axis through its center, the ratio of the tangential acceleration of a point on the rim to the tangential acceleration of a point halfway between the center and the rim is: A. 1 B. 2 C. 1/2 D. 4 E. 1/4

B

For a wheel spinning with constant angular acceleration on an axis through its center, the ratio of the speed of a point on the rim to the speed of a point halfway between the center and the rim is: A. 1 B. 2 C. 1/2 D. 4 E. 1/4

B

A disk is free to rotate on a fixed axis. A force of given magnitude F, in the plane of the disk, is to be applied. Of the following alternatives the greatest angular acceleration is obtained if the force is: A. applied tangentially halfway between the axis and the rim B. applied tangentially at the rim C. applied radially halfway between the axis and the rim D. applied radially at the rim E. applied at the rim but neither radially nor tangentially

B, applied tangentially at rim

Four identical particles, each with mass m, are arranged in the x, y plane as shown. They are connected by light sticks to form a rigid body. If m = 2.0kg and a = 1.0m, the rotational inertia of this array about the y axis is: A. 4.0kg·m2 B. 12kg·m2 C. 9.6kg·m2 D. 4.8kg·m2 E. none of these

B. 12kg·m2

For a wheel spinning on an axis through its center, the ratio of the radial acceleration of a point on the rim to the radial acceleration of a point halfway between the center and the rim is: A. 1 B. 2 C. 1/2 D. 4 E. 1/4

B. 2

A certain object floats in fluids of density 1. 0.9ρ0 2. ρ0 3. 1.1ρ0 Rank these fluids according to the volume displaced by the object, least to greatest. A. 1, 2, 3 B. 3, 2, 1 C. 2, 3, 1 D. 3, 1, 2 E. All are the same

B. 3, 2, 1

To increase the rotational inertia of a solid disk about its axis without changing its mass: A. drill holes near the rim and put the material near the axis B. drill holes near the axis and put the material near the rim C. drill holes at points on a circle near the rim and put the material at points between the holes D. drill holes at points on a circle near the axis and put the material at points between the holes E. do none of the above (the rotational inertia cannot be changed without changing the mass)

B. Drill holes near the axis and put the material near the rim

A bucket of water is pushed from left to right with increasing speed across a horizontal surface. Consider the pressure at two points at the same level in the water. A. It is the same B. It is higher at the point on the left C. It is higher at the point on the right D. At first it is higher at the point on the left but as the bucket speeds up it is lower there E. At first it is higher at the point on the right but as the bucket speeds up it is lower there

B. It is higher at the point on the left

A uniform solid cylinder made of lead has the same mass and the same length as a uniform solid cylinder made of wood. The rotational inertia of the lead cylinder compared to the wooden one is: A. B. C. D. E. greater less same unknown unless the radii are given unknown unless both the masses and the radii are given

B. Less

If the angular velocity vector of a spinning body points out of the page then, when viewed from above the page, the body is spinning: A. B. C. D. E. clockwise about an axis that is perpendicular to the page counterclockwise about an axis that is perpendicular to the page about an axis that is parallel to the page about an axis that is changing orientation about an axis that is getting longer

B. Points out of page = positive, points into page = negative

5. To obtain the absolute pressure from the gauge pressure: A. subtract atmospheric pressure B. add atmospheric pressure C. subtract 273 D. add 273 E. convert to N/m2

B. add atmospheric pressure

The principle of fluid pressure that is used in hydraulic brakes or lifts is that: A. pressure is the same at all levels in a fluid B. increases of pressure are transmitted equally to all parts of a fluid C. the pressure at a point in a fluid is due to the weight of the fluid above it D. increases of pressure can only be transmitted through fluids E. the pressure at a given depth is proportional to the depth in the fluid

B. increases of pressure are transmitted equally to all parts of a fluid

A pirate chest rests at the bottom of an ocean. If the water is still, the net force it exerts on the chest: A. is upward B. is downward C. is zero D. depends on the mass of the chest E. depends on the contents of the chest

B. is downward

If p is a pressure and ρ is a density then p/ρ has units of: A. m2 B. m2/s2 C. N/m2 D. kg/m2 E. m3/kg

B. m2/s2

The equation of continuity for fluid flow can be derived from the conservation of: A. energy B. mass C. angular momentum D. volume E. pressure

B. mass

A block of ice at 0◦ C is floating on the surface of ice water in a beaker. The surface of the water just comes to the top of the beaker. When the ice melts the water level will: A. rise and overflow will occur B. remain the same C. fall D. depend on the initial ratio of water to ice E. depend on the shape of the block of ice

B. remain the same

A small steel ball floats in a half-full container of mercury. When water is added: A. the ball will float on the water B. the ball will rise slightly C. the mercury will float on the water D. the ball will sink to the bottom of the container E. the ball will lower slightly more into the mercury

B. the ball will rise slightly

A closed hemispherical shell of radius R is filled with fluid at uniform pressure p. The net force of the fluid on the curved portion of the shell is given by: A. 2πR2p B. πR2p C. 4πR2p D. (4/3)πR2p E. (4/3)πR3p

B. πR2p

Two wheels roll side-by-side without sliding, at the same speed. The radius of wheel 2 is twice the radius of wheel 1. The angular velocity of wheel 2 is: A. twice the angular velocity of wheel 1 B. the same as the angular velocity of wheel 1 C. half the angular velocity of wheel 1 D. more than twice the angular velocity of wheel 1 E. less than half the angular velocity of wheel 1

C, half

A pulley with a radius of 3.0 cm and a rotational inertia of 4.5×10−3 kg·m2 is suspended from the ceiling. A rope passes over it with a 2.0-kg block attached to one end and a 4.0-kg block attached to the other. The rope does not slip on the pulley. At any instant after the blocks start moving, the object with the greatest kinetic energy is: A. the heavier block B. the lighter block C. the pulley D. either block (the two blocks have the same kinetic energy) E. none (all three objects have the same kinetic energy)

C, the pulley

47. Consider four objects, each having the same mass and the same radius: 1. a solid sphere 2. a hollow sphere 3. a flat disk in the x,y plane 4. a hoop in the x, y plane A. 1,2,3,4 B. 4,3,2,1 C. 1,3,2,4 D. 4,2,3,1 E. 3,1,2,4

C. 1, 3, 2, 4

A boat floating in fresh water displaces 16,000 N of water. How many newtons of saltwater would it displace if it floats in saltwater of specific gravity 1.17? A. 14,500 B. 17,600 C. 16,000 D. 284 E. 234

C. 16,000

When a thin uniform stick of mass M and length L is pivoted about its midpoint, its rotational inertia is ML2/12. When pivoted about a parallel axis through one end, its rotational inertia is: A. ML2/12 B. ML2/6 C. ML2/3 D. 7ML2/12 E. 13M L2 /12

C. ML2 / 3

If a wheel turns with constant angular speed a. each point on its rim moves with constant velocity b. each point on its rim moves with constant acceleration c. the wheel turns through equal angles in equal times d. the angle through which the wheel turns in each second increases as time goes on e. the angle through which the wheel turns in each second decreases as time goes on

C. The wheel turns through equal angles in equal times

A student standardizes the concentration of a saltwater solution by slowly adding salt until an egg will just float. The procedure is based on the assumption that: A. all eggs have the same volume B. all eggs have the same weight C. all eggs have the same density D. all eggs have the same shape E. the salt tends to neutralize the cholesterol in the egg

C. all eggs have the same density

The pressure exerted on the ground by a man is greatest when: A. he stands with both feet flat on the ground B. he stands flat on one foot C. he stands on the toes of one foot D. he lies down on the ground E. all of the above yield the same pressure

C. he stands on the toes of one foot

Gases may be distinguished from other forms of matter by their: A. lack of color B. small atomic weights C. inability to form free surfaces D. ability to flow E. ability to exert a buoyant force

C. inability to form free surfaces

One piston in a hydraulic lift has an area that is twice the area of the other. When the pressure at the smaller piston is increased by ∆p the pressure at the larger piston: A. increases by 2∆p B. increases by ∆p/2 C. increases by ∆p D. increases by 4∆p E. does not change

C. increases by ∆p

The mass of an object: A. is slightly different at different locations on Earth B. is a vector C. is independent of the acceleration due to gravity D. is the same for all objects of the same size and shape E. can be measured directly and accurately on a spring scale

C. is independent of the acceleration due to gravity

A block of ice at 0◦ C containing a piece of cork is floating on the surface of ice water in a beaker. When the ice has melted the water level: A. is higher B. is lower C. is the same D. depends on the initial ratio of water to ice E. depends on the shape of the ice block

C. is the same

A blast of wind tips a sailboat in the clockwise direction when viewed from the stern. When the wind ceases the boat rotates back toward the upright position if, when it is tilted, the center of buoyancy: A. is above the center of gravity B. is below the center of gravity C. is to the right of the center of gravity D. is to the left of the center of gravity E. coincides with the center of gravity

C. is to the right of the center of gravity

An object is raised from the surface of Earth to a height of two Earth radii above Earth. Then: A. its mass increases and its weight remains constant B. both its mass and weight remain constant C. its mass remains constant and its weight decreases D. both its mass and its weight decrease E. its mass remains constant and its weight increases

C. its mass remains constant and its weight decreases

An object floats on the surface of a fluid. For purposes of calculating the torque on it, the buoyant force is taken to act at: A. the center of the bottom surface of the object B. the center of gravity of the object C. the center of gravity of the fluid that the object replaced D. the geometric center of the object E. none of the above

C. the center of gravity of the fluid that the object replaced

A cork floats in water in a bucket resting on the floor of an elevator. The elevator then accelerates upward. During the acceleration: A. the cork is immersed more B. the cork is immersed less C. the cork is immersed the same amount D. at first the cork is immersed less but as the elevator speeds up it is immersed more E. at first the cork is immersed more but as the elevator speeds up it is immersed less

C. the cork is immersed the same amount

A certain object floats in fluids of density 1. 0.9ρ0 2. ρ0 3. 1.1ρ0 Which of the following statements is true? A. the buoyant force of fluid i is greater than the buoyant forces of the other two fluids B. the buoyant force of fluid 3 is greater than the buoyant forces of the other two fluids C. the three fluids exert the same buoyant force D. the object displace the same volume of all three fluids E. none of these are true

C. the three fluids exert the same buoyant force

Two identical blocks of ice float in water as shown. Then: A B A. block A displaces a greater volume of water since the pressure acts on a smaller bottom area B. block B displaces a greater volume of water since the pressure is less on its bottom C. the two blocks displace equal volumes of water since they have the same weight D. block A displaces a greater volume of water since its submerged end is lower in the water E. block B displaces a greater volume of water since its submerged end has a greater area

C. the two blocks displace equal volumes of water since they have the same weight

A fluid is undergoing steady flow. Therefore: A. the velocity of any given molecule of fluid does not change B. the pressure does not vary from point to point C. the velocity at any given point does not vary with time D. the density does not vary from point to point E. the flow is not uphill or downhill

C. the velocity at any given point does not vary with time

A non-viscous incompressible fluid is pumped steadily into the narrow end of a long tapered pipe and emerges from the wide end. The pressure at the input is greater than at the output. A possible explanation is: A. the fluid speed increases from input to output B. the fluid speed is the same at the two ends C. the fluid is flowing uphill D. the fluid is flowing downhill E. the fluid is flowing horizontally

C. the fluid is flowing uphill

A bucket resting on the floor of an elevator contains an incompressible fluid of density ρ. When the elevator has an upward acceleration of magnitude a the pressure difference between two points in a fluid separated by a vertical distance ∆h, is given by: A. ρa∆h B. ρg∆h C. ρ(g +a)∆h D. ρ(g −a)∆h E. ρga∆h

C. ρ(g +a)∆h

A cork floats on the surface of an incompressible liquid in a container exposed to atmospheric pressure. The container is then sealed and the air above the liquid is evacuated. The cork: A. sinks slightly B. rises slightly C. floats at the same height D. bobs up and down about its old position E. behaves erratically

C. floats at the same height

A wheel starts from rest and spins with a constant angular acceleration. As time goes on the acceleration vector for a point on the rim: A. decreases in magnitude and becomes more nearly tangent to the rim B. decreases in magnitude and becomes more early radial C. increases in magnitude and becomes more nearly tangent to the rim D. increases in magnitude and becomes more nearly radial E. increases in magnitude but retains the same angle with the tangent to the rim

D

τ = Iα for an object rotating about a fixed axis, where τ is the net torque acting on it, I is its rotational inertia, and α is its angular acceleration. This expression: A. is the definition of torque B. is the definition of rotational inertia C. is the definition of angular acceleration D. follows directly from Newton's second law E. depends on a principle of physics that is unrelated to Newton's second law

D

A force with a given magnitude is to be applied to a wheel. The torque can be maximized by: A. applying the force near the axle, radially outward from the axle B. applying the force near the rim, radially outward from the axle C. applying the force near the axle, parallel to a tangent to the wheel D. applying the force at the rim, tangent to the rim E. applying the force at the rim, at 45◦ to the tangent

D applying the force at the rim, tangent to the rim

4. A forward force on the axle accelerates a rolling wheel on a horizontal surface. If the wheel does not slide the frictional force of the surface on the wheel is: A. zero B. in the forward direction C. in the backward direction D. in the upward direction E. in the downward direction

D, in the upward direction

1 Pa is: A. 1 N/m B. 1 m/N C. 1 kg/m ·s D. 1 kg/m ·s2 E. 1 N/m ·s

D. 1 kg/m ·s2

6. Barometers and open-tube manometers are two instruments that are used to measure pressure A. Both measure gauge pressure B. Both measure absolute pressure C. Barometers measure gauge pressure and manometers measure absolute pressure D. Barometers measure absolute pressure and manometers measure gauge pressure E. Both measure an average of the absolute and gauge pressures

D. Barometers measure absolute pressure and manometers measure gauge pressure

A disk starts from rest and rotates around a fixed axis, subject to a constant net torque. The work done by the torque during the second 5 s is as the work done during the first 5 s. A. the same B. twice as much C. half as much D. four times as much E. one-fourth as much

D. Four times as much

A uniform disk, a thin hoop, and a uniform sphere, all with the same mass and same outer radius, are each free to rotate about a fixed axis through its center. Assume the hoop is connected to the rotation axis by light spokes. With the objects starting from rest, identical forces are simultaneously applied to the rims, as shown. Rank the objects according to their angular accelerations, least to greatest. A. disk, hoop, sphere B. hoop, disk, sphere C. hoop, sphere, disk D. hoop, disk, sphere E. sphere, disk, hoop

D. Hoop, disk, spehere

Which of the following five statements, concerning the upper surface pressure of a liquid, is FALSE? A. It is independent of the surface area B. It is the same for all points on that surface C. It would not increase if the liquid depth were increased D. It would increase if the liquid density were increased E. It would increase if the atmospheric pressure increased

D. It would increase if the liquid density were increased

The rotational inertia of a thin cylindrical shell of mass M, radius R, and length L about its central axis (X—X) is: A. MR2/2 B. ML2/2 C. ML2 D. MR2 E. none of these

D. MR2

The fan shown has been turned on and is now slowing as it rotates clockwise. The direction of the acceleration of the point X on the fan tip could be: A. B. C. ↓ D. ←

D. Negative, left

The rotational inertia of a wheel about its axle does not depend upon its: A. B. C. D. E. diameter mass distribution of mass speed of rotation material composition

D. Speed of rotation material composition

When the speed of a rear-drive car is increasing on a horizontal road the direction of the frictional force on the tires is: A. forward for all tires B. backward for all tires C. forward for the front tires and backward for the rear tires D. backward for the front tires and forward for the rear tires E. zero

D. backward for the front tires and forward for the rear tires

An astronaut in an orbiting spacecraft feels "weightless" because she: A. is beyond the range of gravity B. is pulled outward by centrifugal force C. has no acceleration D. has the same acceleration as the spacecraft E. is outside Earth's atmosphere

D. has the same acceleration as the spacecraft

4. Mercury is a convenient liquid to use in a barometer because: A. it is a metal B. it has a high boiling point C. it expands little with temperature D. it has a high density E. it looks silvery

D. it has a high density

In a stationary homogeneous liquid: A. pressure is the same at all points B. pressure depends on the direction C. pressure is independent of any atmospheric pressure on the upper surface of the liquid D. pressure is the same at all points at the same level E. none of the above

D. pressure is the same at all points at the same level

A bucket resting on the floor of an elevator contains an incompressible fluid of density ρ. When the elevator has a downward acceleration of magnitude a the pressure difference between two points in a fluid, separated by a vertical distance ∆h, is given by: A. ρa∆h B. ρg∆h C. ρ(g +a)∆h D. ρ(g −a)∆h E. ρga∆h

D. ρ(g −a)∆h

The magnitude of the acceleration of a point on a spinning wheel is increased by a factor of 4 if: A. B. C. D. E. the magnitudes of the angular velocity and the angular acceleration are each multiplied by a factor of 4 the magnitude of the angular velocity is multiplied by a factor of 4 and the angular acceleration is not changed the magnitudes of the angular velocity and the angular acceleration are each multiplied by a factor of 2 the magnitude of the angular velocity is multiplied by a factor of 2 and the angular acceleration is not changed the magnitude of the angular velocity is multiplied by a factor of 2 and the magnitude of the angular acceleration is multiplied by a factor of 4

E

A and B are two solid cylinders made of aluminum. Their dimensions are shown. The ratio of the rotational inertia of B to that of A about the common axis X—X is: A. 2 B. 4 C. 8 D. 16 E. 32

E. 32 Mass = density x volume Volume for cylinder = pi 4^2 * l

The rotational inertia of a solid uniform sphere about a diameter is (2/5)MR2, where M is its mass and R is its radius. If the sphere is pivoted about an axis that is tangent to its surface, its rotational inertia is.. MR2 (2/5)M R2 (3/5)M R2 (5/2)M R2 (7/5)M R2

E. 7/5 M R2

The vessels shown below all contain water to the same height. Rank them according to the pressure exerted by the water on the vessel bottoms, least to greatest. A. 1, 2, 3, 4 B. 3, 4, 2, 1 C. 4, 3, 2, 1 D. 2, 3, 4, 1 E. All pressures are the same

E. All pressures are the same

A solid wheel with mass M, radius R, and rotational inertia MR2/2, rolls without sliding on a horizontal surface. A horizontal force F is applied to the axle and the center of mass has an acceleration a. The magnitudes of the applied force F and the frictional force f of the surface, respectively, are: A. F = M a, f = 0 B. F = M a, f = M a/2 C. F = 2M a, f = M a D. F = 2M a, f = M a/2 E. F = 3M a/2, f = M a/2

E. F = 3M a/2, f = M a/2

The meter stick shown below rotates about an axis through the point marked •, 20 cm from one end. Five forces act on the stick: one at each end, one at the pivot point, and two 40 cm from one end, as shown. The magnitudes of the forces are all the same. Rank the forces according to the magnitudes of the torques they produce about the pivot point, least to greatest. A. F1, F2, F3, F4, F5 B. F1 and F2 tie, then F3 , F4 , F5 C. F2 and F5 tie, then F4 , F1 , F3 D. F2 , F5 , F1 and F3 tie, then F4 E. F2 and F5 tie, then F4, then F1 and F3 tie

E. F2 & F5 Tie, then F4, Then f1 & F3 tie

Which of the following statements about Pascal's principle is true? A. It is valid only for incompressible fluids B. It explains why light objects float C. It explains why the pressure is greater at the bottom of a lake than at the surface D. It is valid only for objects that are less dense than water E. None of the above are true

E. None of the above are true

Water is pumped into one end of a long pipe at the rate of 40 L/min. It emerges at the other end at 24 L/min. A possible reason for this decrease in flow is: A. the water is being pumped uphill B. the water is being pumped downhill C. the diameter of the pipe is not the same at the two ends D. friction in the pipe E. a leak in the pipe

E. a leak in the pipe

A U-tube has dissimilar arms, one having twice the diameter of the other. It contains an incompressible fluid and is fitted with a sliding piston in each arm, with each piston in contact with the fluid. When the piston in the narrow arm is pushed down a distance d, the piston in the wide arm rises a distance: A. d B. 2d C. d/2 D. 4d E. d/4

E. d/4

A fluid is undergoing "incompressible" flow. This means that: A. the pressure at a given point cannot change with time B. the velocity at a given point cannot change with time C. the velocity must be the same everywhere D. the pressure must be the same everywhere E. the density cannot change with time or location

E. the density cannot change with time or location

Several cans of different sizes and shapes are all filled with the same liquid to the same depth. Then: A. the weight of the liquid is the same for all cans B. the force of the liquid on the bottom of each can is the same C. the least pressure is at the bottom of the can with the largest bottom area D. the greatest pressure is at the bottom of the can with the largest bottom area E. the pressure on the bottom of each can is the same

E. the pressure on the bottom of each can is the same

A large tank filled with water has two holes in the bottom, one with twice the radius of the other. In steady flow the speed of water leaving the larger hole is the speed of the water leaving the smaller. A. twice B. four times C. half D. one-fourth E. the same as

E. the same as

The diagram shows a pipe of uniform cross section in which water is flowing. The directions of flow and the volume flow rates (in cm3/s) are shown for various portions of the pipe. The direction of flow and the volume flow rate in the portion marked A are: A. ↓and3cm3/s B. ↑and7cm3/s C. ↓and9cm3/s D. ↑ and 11 cm3/s E. ↓ and 15 cm3/s

E. ↓ and 15 cm3/s

Two carts (A and B), having spring bumpers, collide as shown. Cart A has a mass of 2 kg and is initially moving to the right. Cart B has a mass of 3 kg and is initially stationary. When the separation between the carts is a minimum:

the kinetic energy of the system is at a minimum

If a projectile hits a stationary target, and the projectile rebounds and travels back the way it came,

the mass of the projectile is much less than the mass of the target.

A wheel rolls without sliding along a horizontal road as shown. The velocity of the center of the wheel is represented by −→. Point P is painted on the rim of the wheel. The instantaneous velocity of point P is:

zero.

A phonograph turntable, initially rotating at 0.75 rev/s, slows down and stops in 30 s. The magnitude of its average angular acceleration for this process is:

π/20 rad/s2