Physics Final Even Cake Tastes Like Apples

A block of mass 3 kg, initially at rest, is pulled along with frictionless, horizontal surface with a force shown as a function of time by the graph above. The acceleration of the block is A. 4/3 m/s2 B. 2 m/s2 C. 8 m/s2 D. 12 m/s2

A. 4/3 m/s2

Each of the diagrams below represents two weights connected by a massless string which passes over a massless, frictionless pulley. In which diagram will the magnitude of the acceleration be the largest? A. 2/1 B. 4/3 C. 8/5 D. 10/6

A.2/1

The magnitude of the normal force excepted on the block by the plane is A. greater than 20 N B. greater than zero but less than 20 N C. equal to 20 N D. zero

B. greater than zero but less than 20 N

A block of weight W is pulled along a horizontal surface at a constant speed v by a force F, which acts at an angle of (Theta) with the horizontal, as shown above. The normal force exerted on the block by the surface has magnitude A. greater than W B. greater than zero but less than W C. equal to W D. zero

B. greater than zero but less than W

Assume the objects in the following diagrams have equal mass and the strings holding them in place are identical. In which case would the most likely to break? A. one string up and down B. two strings straight left and right C. two strings left and right 45 degrees D. All same likely to break

B. two strings straight left and right

A spaceman of mass 80 kg is sitting in a spacecraft near the surface of the Earth. The spacecraft is accelerating upward at five times the acceleration due to gravity. What is the force of the spaceman on the spacecraft? (A) 4800 N (B) 4000 N (C) 3200N (D) 800 N

(A) 4800 N

When the speed of a rear-drive car is increasing on a horizontal road, what is the direction of the frictional force on the tires? (A) backward on the front tires and forward on the rear tires (B) forward on the front tires and backward on the rear tires (C) forward on all tires (D) backward on all tires

(A) backward on the front tires and forward on the rear tires

A 50-kg student stands on a scale in an elevator. At the moment the elevator has a downward acceleration of 1.0 m / s2 and an upward velocity of 3.0 m / s, the scale reads approximately (A) 350 N (B) 450 N (C) 500 N (D) 550 N

(B) 450 N

A simple Atwood's machine is shown in the diagram above. It is composed of a frictionless lightweight pulley with two cubes connected by a light string. If cube A has a mass of 4.0 kg and cube B has a mass of 6.0kg, the system will move such that cube B accelerates downwards. string between the pulley and the cubes? (A) TA-47 N; 7B 71 N (B) TA -47 N; TB-47N (C) TA-47N; TB 42 N (D) TA-39 N;7B-39 N

(B) TA -47 N; TB-47N

A crate of toys remains at rest on a sleigh as the sleigh is pulled up a hill with an increasing speed. The crate is not fastened down to the sleigh. What force is responsible for the crate's increase in speed up the hill? (A) the contact force (normal force) of the ground on the sleigh (B) the force of static friction of the sleigh on the crate (C) the gravitational force acting on the sleigh (D) no force is needed gravitational for

(B) the force of static friction of the sleigh on the crate

A mass, M, is at rest on a frictionless surface, connected to an ideal horizontal spring that is unstretched. A person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force. The spring is brought back to equilibrium and the mass connected to it is now extended back 30 cm from equilibrium, what is the necessary force applied by the person to hold the m stationary there? (A) 20.0N (B) 14.1 N (C) 10.ON (D) 7.07 N

(C) 10.ON

A 6.0 kg block initially at rest against a wall by a 100 N force as shown. The coefficient of kinetic friction is 0.30 while the coefficient of static friction is 0.50. What is true of friction acting on the block after a second time? (A) Static friction acts upward on the block. (B) Kinetic friction acts upward on the block (C) Kinetic friction acts downward on the block. (D) Static friction acts downward on the block.

(C) Kinetic friction acts downward on the block.

The graph at left shows the relationship between the mass of a number of rubber halters and their resulting weight on some far-off planet. The slope of the graph is a representation of the: (A) mass of a stopper (B) density of a stopper (C) acceleration due to gravity (D) number of stoppers for each unit of weight

(C) acceleration due to gravity

A tractor-trailer is traveling down the road. The mass of the trailer is 4 times the mass of the tractor. If the tractor accelerates forward, the force that the trailer applies on the tractor is (A) 4 times greater than the force of the tractor on the trailer (B) 2 times greater than the force of the tractor on the trailer. (C) equal to the force of the tractor on the trailer. (D) 1/4 the force of the tractor on the trailer

(C) equal to the force of the tractor on the trailer.

A wooden box is shown in the diagram as shown in the diagram. A. The box is then drawn across the plate as shown in the diagram. case compare to the horizontal case ? (A) The frictional force is the same in both cases (B) the inclined case has a greater frictional force (C) the inclined case has the least frictional force (D) the frictional force increases with angle until the angle is 90 °, then drops to zero

(C) the inclined case has the least frictional force

Two blocks of mass 1.0 kg and 3.0 kg are connected by a string which has a tension of 2.0 N. Force F acts in the direction shown to the right. Assuming friction is negligible, what is the value of F? (A) 2.0N (B) 4.0N (C) 6.0 N (D) 8.0 N

(D) 8.0 N

Block 1 is stacked on top of block 2. Block 2 is connected by a light cord to block 3, which is pulled along a frictionless surface with a force F as shown in the diagram. Block 1 is accelerated at the same rate as block 2 because of the frictional forces between the two blocks. If all three blocks have the same mass m, what is the minimum coefficient of static friction between block 1 and block 2? (A) 2F/mg (B)F/mg (C) 3F/2mg (D) F/3mg

(D) F/3mg

A skydiver is falling at terminal velocity before opening her parachute. After opening her parachute, she falls at a much smaller terminal velocity. How does the total upward force before she opens her parachute compare to the total upward force after she opens her parachute? (A) The ratio of the forces is equal to the ratio of the velocities. (B) The upward force with the parachute will depend on the size of the parachute. (C) The upward force before the parachute will be greater because of the greater velocity (D) The upward force in both cases must be the same.

(D) The upward force in both cases must be the same

Three identical laboratory carts A, B, and C are each subject to a constant force Fa. Fa.and Fc, respectively One or more of these forces may be zero. The diagram below shows the position of each cart at each second of an 8.0 second interval. Which car has the greatest average velocity during the interval? (A)A (B) B (C)C (D) all three average velocities are equal

(D) all three average velocities are equal

Given the three masses as shown in the diagram above, if the coefficient of kinetic friction between the large mass (m2) and the table is u, what would be the upward acceleration of the small mass (m)? The mass and friction of the cords and pulleys are small enough to produce a negligible effect on the system. (A) g(m + m2u)/(m + m2 + m3) (B) gu(mi +m2+m/ (m1 -m2- m3) (C) gu(m - m2- m3)/ (mi + m2 + m3) (D) g(mj-um2-m3)/ (mi+ m2+ m3)

(D) g(mj-um2-m3)/ (mi+ m2+ m3)

A force F is used to hold a block of mass m on an incline as shown in the diagram (see above). The plane makes an angle of 0 with the horizontal and F is perpendicular to the plane. The coefficient of friction between the plane and the block is u. What is the minimum force, F, necessary to keep the block at rest? (A) mgcose (B) mgsine (C) mgsin6/u (D) mg(sine-ucos)/u

(D) mg(sine-ucos)/u

A small box of mass is placed on top of a larger box of mass 2m as shown in the diagram at right. When a force is applied to the large box, both boxes accelerate to the right with the same acceleration. If the coefficient of friction between all surfaces is u, what would be the force accelerating the smaller mass? A. (F/3) - mgu B. F - 3mgu C. F - mgu D. (F - mgu)/3

A. (F/3) - mgu

Three blocks (mi, m2, and m3) are sliding at a constant velocity across a rough surface as shown in the diagram above. The coefficient of kinetic friction between each block and the surface is u. What would be the force of mi on m2? A. (m2 + m3)gu B. F - (m2 - m3)gu C. F D. m1gu - (m2 + m3)gu

A. (m2 + m3)gu

A rope of negligible mass supports a block that weighs 30 N, as shown above. The breaking strength of the rope is 50 N. The largest acceleration that can be given to the block by pulling on it with the rope without breaking the rope most nearly A. 6.7 m/s2 B. 10 m/s2 C 16.7 m/s2 D. 26.7 m/s2

A. 6.7 m/s2

A student pulls a wooden box along a rough horizontal floor at constant speed by means of a force as shown to the right. Which of the following must be true? A. P > f and N < W A. P > f and N = W A. P = f and N > W A. P = f and N = W

A. P > f and N < W

A homeowner pushes a lawn mower across a horizontal patch of grass with a constant speed by applying a force P. The arrows in the diagram correctly indicate the directions but not necessarily the magnitudes of the various forces on the lawn mower. Which of the following relations among the various force magnitudes, W.f. N, P is correct? A. P > f and N > W B. P < f and N = W C. P > f and N < W D. P = f and N > W

A. P > f and N > W

A mass is suspended from the roof of a lift (elevator) by means of a spring balance. The lift (elevator) is moving upwards and the readings of the spring balance are noted as follows: Speeding up: Ru Constant speed: Rc Slowing down: RD Which of the following is a correct relationship between the readings? A. Ru > Rc B. Ru = RD C. Rc < RD D. Rc < RD

A. Ru > Rc

Multiple correct: Three forces act on an object. If the object is moving to the right translational equilibrium, which of the following must be true? Select two A. The vector sum of the three forces must be equal to zero. B. All three forces must be parallel C. The magnitudes of three forces must be equal D. The object must be moving at a constant speed

A. The vector sum of the three forces must be equal to zero. D. The object must be moving at a constant speed

The 10.0 kg box shown in the figure to the right sliding to the right along the floor. A horizontal force of 10.0 N is being applied to the right. The coefficient of kinetic friction between the box and the floor is 0.20. The box is moving with A. acceleration to the left B. acceleration to the right C. constant speed and velocity D. constant speed but not constant velocity

A. acceleration to the left

A horizontal, uniform board of weight 125 N and length 4 m is supported by vertical chains at each end. A person weighing 500 N is hanging from board. The tension in the right chain is 250 N. Which of the following describes where the person is hanging? A. between the chains, but closer to the left-hand chain B. between the chains, but closer to the right-hand chain C. Right in the middle of the board D. directly below the chains

A. between the chains, but closer to the left-hand chain

A box slides to the right across a horizontal floor. A person called Ted exerts a force T to the right on the box. A person called Mario exerts a force M to the left, which is half as large as the force T. Given that there is friction f and the box accelerates to the right, rank the sizes of these three forces exerted on the box. A. f < M < T B. M < f < T C. M < T < f D. f = M < T

A. f < M < T

A block of mass 3m can move without friction on a horizontal table. This block is attached to another block of mass m by a cord that passes over a frictionless pulley, as shown above. If the masses of the cord and the pulley are negligible, what is the magnitude of the acceleration of the descending block? A. g/4 B. g/3 C. 2g/3 D. g

A. g/4

A simple Atwood's machine remains motionless when equal masses M are placed on each end of the chord. When a small mass m is added to one side, the masses have an acceleration a. What is Mf? You may neglect friction and the mass of the cord and pulley. A. m(g-a)/2a B. 2m(g-a)/a C. 2m(g+a)/a D. m(g+a)/2a

A. m(g-a)/2a

Multiple Correct: The cart of mass 10 kg shown above moves without frictional loss on a level table. A 10 N force pulls on the cart horizontally to the right. At the same time, a 30 N force at an angle of 60 degrees above the horizontal pulls the cart to the left. Which of the following describes a manner in which this cart could be moving? Select two. A. moving left and speeding up B. moving left and slowing down C. moving right and speeding up D. moving right and slowing down

A. moving left and speeding up D. moving right and slowing down

The parabola above (y= x^2) is a graph of speed v as a function of time t for an object. Which of the following graphs best represents the magnitude F of the net force exerted on the object as a function of time t? A. y = 2x B. y = x^2 C. y = x^2 (moved right) D. y = -x^2 (moved right and up)

A. y = 2x

A ball falls straight down through the air under the influence of gravity. There is a retarding force F on the ball with magnitude given by F = bv, where v is the speed of the ball and b is a positive constant. The ball reaches a terminal velocity after a time t. The magnitude of the acceleration at time t/2 is A. Increasing B. Decreasing C. 10 m/s/s D. Zero

B. Decreasing

Three identical laboratory carts A, B, and C are each subject to a constant force Fa. Fa.and Fc, respectively One or more of these forces may be zero. The diagram below shows the position of each cart at each second of an 8.0 second interval. How does the magnitude of the force acting on each car compare? A. Fa > Fb > Fc B. Fa = Fc > Fb C. Fa > Fc = Fb D. Fa = Fb > Fc

B. Fa = Fc > Fb

A ball initially moves horizontally with velocity vi, as shown above. It is then struck by a stick. After leaving the stick, the ball moves vertically with a velocity vf, which is smaller magnitude than vi. Which of the following vectors best represents the direction of the average force that the stick excerpts on the ball? A. horizontal left B. Horizontal left 30 degrees incline C. Straight up D. Horizontal left 60 degrees incline

B. Horizontal left 30 degrees incline

Two people are pulling on the ends of a rope. Each person pulls with a force of 100 N. The tension in the rope is A. 0 N B. 50 N C. 100 N D. 200 N

C. 100 N

A horizontal, uniform board of weight 125 N and length 4 m is supported by vertical chains at each end. A person weighing 500 N is hanging from board. The tension in the right chain is 250 N. What is the tension in the left chain? A. 125 N B. 250 N C. 375 N D. 625 N

C. 375 N

Two identical blocks of weight W are placed one on top of the other as shown in the diagram above. The upper block is tied to the wall. The lower block is pulled to the right with a force F. The coefficient of static friction between all surfaces in contact is u. What is the largest force F that can be exerted before the lower block starts to slip? A. uW B. 2uW C. 3uW D. 3uW/2

C. 3uW

Three blocks of masses 3m, 2m, and are connected to strings A, B, and C as shown above. The coefficient of friction between each block and the surface is the same. Which string must be strong in order not to break? A. A B. B C. C D. They must all be the same strength

C. C

A ball of mass m is suspended from two strings of unequal lengeths as shown above. The magnitudes of the tensions T1 and T2 in the string must satisfy which of the following relations. A. T1 = T2 B. T1 > T2 C. T1 < T2 D. T1 + T2 = mg

C. T1 < T2

Two massless springs, of constant spring k, and k2, are hung from a horizontal support. A block of weight 12 N is suspended from the peer of springs, as shown above. When the block is in equilibrium, each spring is stretched an additional 24 cm. Thus, the equivalent spring of the two-spring system is 12 N / 24 cm-N / cm. Which of the following statements is correct about k and k2? A. k1 = k2 = 0.25 N/cm B. 1/k1 + 1/k2 = 1/.05N/cm C. k1 - k2 = .5N/cm D. k1 + k2 = .5N/cm

D. k1 + k2 = .5N/cm

A block of mass is accelerated across a rough surface by a force of magnitude which is exerted at an angle to the horizontal, as shown above. The frictional force on the block What is the acceleration of the block? A. F/m B. (Fcos(theta))/m C. (F-f)/m D. (Fcos(theta)-f)/m

D. (Fcos(theta)-f)/m

When the frictionless system with a 2 kg brick followed by a 1 kg brick is accelerated by an applied force of the magnitude the tension in the string between the bricks is A. F B. 2/3 F C. 1/2 F D. 1/3 F

D. 1/3 F

Which of the following correctly indicates the magnitudes of the forces acting up and down on the incline? A. 20N down the plane, 16N up the plane B. 4N down the plane, 4N up the plane C. 0N down the plane, 4N up the plane D. 10N down the plane, 6N up the plane

D. 10N down the plane, 6N up the plane

For which of the following motions of an object must the acceleration always be zero? A. Any motion in a straight line B. Simple harmonic motion C. Any motion at contestant D. Any single object in motion with constant momentum

D. Any single object in motion with constant momentum

A uniform rope of weight 50 N hangs from a hook as shown above. A box of weight 100N hangs from the rope. What is the tension in the rope? A. 75 N throughout the rope B. 100 N throughout the rope C. 150 N throughout the rope D. It varies from 100 N at the bottom of the rope to 150 N at the top

D. It varies from 100 N at the bottom of the rope to 150 N at the top

Which of the folowing diagrams best represents the gravitational force W. The frictional force f. and the normal force N act on the block? A. N due north, f down bottom of block, w perpendicular to base B. N due north, f up bottom of block, w due south C. N perpendicular to top, f up bottom of block, w perpendicular to base D. N perpendicular to top, f up bottom of block, w due south

D. N perpendicular to top, f up bottom of block, w due south

Two masses, are connected by a cord and arranged as shown in the diagram with sliding friction along the frictionless surface and hanging from a light frictionless pulley. What would be the mass of the mass mass, m, if both the sliding mass, mi, and the tension, T, in the cord are known? A. m1g-T/g B. (1/2)Tg C. m1(T-g)/(gm1-T) D. Tm1/(gm1-T)

D. Tm1/(gm1-T)

When an object of weight W is suspended from the center of a massless string as shown above, the tension at any point in the string is A. 2Wcos(Theta) B. 1/2 Wcos(Theta) C. W/(2cos(Theta)) D. W/(cos(Theta))

D. W/(cos(Theta))

A ball is thrown and follows a parabolic path, as shown above. Air friction is negligible. Point Q is the highest point on the path. Which of the following best indicates the direction of the net force on the ball at point P? A. arrow right 30 degree inline B. arrow right C. arrow right 30 degree decline D. arrow straight down

D. arrow straight down