Question 1

You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is

Accepted Answer

A)  exactly 1500 N only if the box does not move. 
B)  exactly 1500 N whether or not the box moves. 
C)  greater than 1500 N if the box moves. 
D)  less than 1500 N if the box moves. 
E)  greater than 1500 N if the bat bounces back. 
A)  exactly 1500 N only if the box does not move. 
B)  exactly 1500 N whether or not the box moves. 
C)  greater than 1500 N if the box moves. 
D)  less than 1500 N if the box moves. 
E)  greater than 1500 N if the bat bounces back.

Question 2

Two blocks are connected by a string that goes over an ideal pulley as shown in the figure. Block A has a mass of 3.00 kg and can slide over a rough plane inclined 30.0° to the horizontal. The coefficient of kinetic friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the acceleration of the blocks?

Accepted Answer

A)  0.392 m/s2 
B)  1.96 m/s2 
C)  3.12 m/s2 
D)  5.35 m/s2 
E)  0.00 m/s2 
A)  0.392 m/s2 
B)  1.96 m/s2 
C)  3.12 m/s2 
D)  5.35 m/s2 
E)  0.00 m/s2

Question 3

A series of weights connected by very light cords are given an upward acceleration of 4.00 m/s2 by a pull P, as shown in the figure. A, B, and C are the tensions in the connecting cords. The SMALLEST of the three tensions, A, B, and C, is closest to

Accepted Answer

A)  80.0 N. 
B)  196 N. 
C)  276 N. 
D)  483 N. 
E)  621 N. 
A)  80.0 N. 
B)  196 N. 
C)  276 N. 
D)  483 N. 
E)  621 N.

Question 4

Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N. What is the mass M?

Accepted Answer

A)  8.33 kg 
B)  33.9 kg 
C)  35.0 kg 
D)  52.8 kg 
E)  95.0 kg 
A)  8.33 kg 
B)  33.9 kg 
C)  35.0 kg 
D)  52.8 kg 
E)  95.0 kg

Question 5

The figure shows two 1.0 kg-blocks connected by a rope. A second rope hangs beneath the lower block. Both ropes have a mass of 250 g. The entire assembly is accelerated upward at 2.3 m/s2 by force   . What is the tension at the top end of rope 1?

Accepted Answer

A)  18 N 
B)  15 N 
C)  2.9 N 
D)  3.5 N 
A)  18 N 
B)  15 N 
C)  2.9 N 
D)  3.5 N

Question 6

A locomotive is pulling 19 freight cars, each of which is loaded with the same amount of weight. The mass of each freight car (with its load) is 37,000 kg. If the train is accelerating at 0.22 m/s2 on a level track, what is the tension in the coupling between the second and third cars? (The car nearest the locomotive is counted as the first car, and friction is negligible.)

Accepted Answer

Question 7

Two objects having masses m1 and m2 are connected to each other as shown in the figure and are released from rest. There is no friction on the table surface or in the pulley. The masses of the pulley and the string connecting the objects are completely negligible. What must be true about the tension T in the string just after the objects are released?

Accepted Answer

A)  T = m2g 
B)  T > m2g 
C)  T 2g 
D)  T = m1g 
E)  T > m1g 
A)  T = m2g 
B)  T > m2g 
C)  T 2g 
D)  T = m1g 
E)  T > m1g

Question 8

In order to get an object moving, you must push harder on it than it pushes back on you.

Accepted Answer

A) True 
 B)False

Question 9

In order to lift a bucket of concrete, you must pull up harder on the bucket than it pulls down on you.

Accepted Answer

A) True 
 B)False

Question 10

The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes it
0.90 s to reach the floor. What is the mass m of the other block? The pulley has no appreciable mass or friction.

Accepted Answer

A)  60 kg 
B)  54 kg 
C)  48 kg 
D)  42 kg 
A)  60 kg 
B)  54 kg 
C)  48 kg 
D)  42 kg

Question 11

Two unequal masses M and m (M > m) are connected by a light cord passing over a pulley of negligible mass, as shown in the figure. When released, the system accelerates. Friction is negligible. Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 12

A 4.00-kg box sits atop a 10.0-kg box on a horizontal table. The coefficient of kinetic friction between the two boxes and between the lower box and the table is 0.600, while the coefficient of static friction between these same surfaces is 0.800. A horizontal pull to the right is exerted on the lower box, as shown in the figure, and the boxes move together. What is the friction force on the UPPER box?

Accepted Answer

A)  19.3 N to the right 
B)  19.3 N to the left 
C)  23.5 N to the right 
D)  31.4 N to the right 
E)  31.4 N to the left 
A)  19.3 N to the right 
B)  19.3 N to the left 
C)  23.5 N to the right 
D)  31.4 N to the right 
E)  31.4 N to the left

Question 13

Three objects are connected as shown in the figure. The strings and frictionless pulleys have negligible masses, and the coefficient of kinetic friction between the 2.0-kg block and the table is 0.25. What is the acceleration of the 2.0-kg block?

Accepted Answer

A)  2.5 m/s2 
B)  1.7 m/s2 
C)  3.2 m/s2 
D)  4.0 m/s2 
A)  2.5 m/s2 
B)  1.7 m/s2 
C)  3.2 m/s2 
D)  4.0 m/s2

Question 14

In the figure, two wooden blocks each of 0.30 kg mass are connected by a string that passes over a very light frictionless pulley. One block slides on a horizontal table, while the other hangs suspended by the string, as shown in the figure. At time t = 0, the suspended block is 0.80 m over the floor, and the blocks are released from rest. After 2.5 s, the suspended block reaches the floor. What is the coefficient of kinetic friction between the table and the sliding block?

Accepted Answer

A)  0.35 
B)  0.52 
C)  0.84 
D)  0.65 
E)  0.95 
A)  0.35 
B)  0.52 
C)  0.84 
D)  0.65 
E)  0.95

Question 15

A 6.00-kg block is in contact with a 4.00-kg block on a horizontal frictionless surface as shown in the figure. The 6.00-kg block is being pushed by a horizontal 20.0-N force as shown. What is the magnitude of the force that the 6.00-kg block exerts on the 4.00-kg block?

Accepted Answer

A)  6.00 N 
B)  20.0 N 
C)  8.00 N 
D)  4.00 N 
E)  10.0 N 
A)  6.00 N 
B)  20.0 N 
C)  8.00 N 
D)  4.00 N 
E)  10.0 N

Question 16

A system comprised blocks, a light frictionless pulley, and connecting ropes is shown in the figure. The 9.0-kg block is on a perfectly smooth horizontal table. The surfaces of the 12-kg block are rough, with µk = 0.30 between the block and the table. If the 5.0-kg block accelerates downward when it is released, find its acceleration.

Accepted Answer

A)  1.0 m/s2 
B)  1.2 m/s2 
C)  1.4 m/s2 
D)  1.6 m/s2 
E)  1.8 m/s2 
A)  1.0 m/s2 
B)  1.2 m/s2 
C)  1.4 m/s2 
D)  1.6 m/s2 
E)  1.8 m/s2

Question 17

A pickup truck is moving at 25 m/s with a toolbox of mass m resting on the bed of the truck 2.5 m behind the cab. Suddenly the brakes are applied, causing the toolbox to slide, and the truck comes to a stop in 4.7 s. The coefficient of kinetic friction between the toolbox and the bed of the truck is 0.28. After the brakes are applied, how much time elapses before the toolbox strikes the cab?

Accepted Answer

The answer of A pickup truck is moving at 25...

Question 18

The International Space Station has a mass of 1.8 × 105 kg. A 70.0-kg astronaut inside the station pushes off one wall of the station so she accelerates at 1.50 m/s2. What is the magnitude of the acceleration of the space station as the astronaut is pushing off the wall? Give your answer relative to an observer who is space walking and therefore does not accelerate with the space station due to the push.

Accepted Answer

A)  5.8 × 10-4 m/s2 
B)  1.50 m/s2 
C)  4.7 × 10-4 m/s2 
D)  zero 
E)  3.9 × 10-3 m/s2 
A)  5.8 × 10-4 m/s2 
B)  1.50 m/s2 
C)  4.7 × 10-4 m/s2 
D)  zero 
E)  3.9 × 10-3 m/s2

Question 19

Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N. What is the tension in wire A?

Accepted Answer

A)  87.5 N 
B)  245 N 
C)  280 N 
D)  333 N 
E)  517 N 
A)  87.5 N 
B)  245 N 
C)  280 N 
D)  333 N 
E)  517 N

Question 20

A wooden block A of mass 4.0 kg slides on a frictionless table when pulled using a massless string and pulley array by a hanging box B of mass 5.0 kg, as shown in the figure. What is the acceleration of block A as it slides on the frictionless table? Hint: Think carefully about the acceleration constraint.

Accepted Answer

A)  4.1 m/s2 
B)  3.5 m/s2 
C)  3.1 m/s2 
D)  2.7 m/s2 
A)  4.1 m/s2 
B)  3.5 m/s2 
C)  3.1 m/s2 
D)  2.7 m/s2

Exam 7: Newtons Third Law

You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is

A series of weights connected by very light cords are given an upward acceleration of 4.00 m/s2 by a pull P, as shown in the figure. A, B, and C are the tensions in the connecting cords. The SMALLEST of the three tensions, A, B, and C, is closest to

Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N. What is the mass M?

The figure shows two 1.0 kg-blocks connected by a rope. A second rope hangs beneath the lower block. Both ropes have a mass of 250 g. The entire assembly is accelerated upward at 2.3 m/s2 by force . What is the tension at the top end of rope 1?

In order to get an object moving, you must push harder on it than it pushes back on you.

In order to lift a bucket of concrete, you must pull up harder on the bucket than it pulls down on you.

The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes it 0.90 s to reach the floor. What is the mass m of the other block? The pulley has no appreciable mass or friction.

Two unequal masses M and m (M > m) are connected by a light cord passing over a pulley of negligible mass, as shown in the figure. When released, the system accelerates. Friction is negligible. Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

Three objects are connected as shown in the figure. The strings and frictionless pulleys have negligible masses, and the coefficient of kinetic friction between the 2.0-kg block and the table is 0.25. What is the acceleration of the 2.0-kg block?

A 6.00-kg block is in contact with a 4.00-kg block on a horizontal frictionless surface as shown in the figure. The 6.00-kg block is being pushed by a horizontal 20.0-N force as shown. What is the magnitude of the force that the 6.00-kg block exerts on the 4.00-kg block?

Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N. What is the tension in wire A?

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Dynamics Ii: Motion in a Plane

Impulse and Momentum

Energy

Work

Rotation of a Rigid Body

Newtons Theory of Gravity

Oscillations

Fluids and Elasticity

A Macroscopic Description of Matter

Work, Heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Traveling Waves

Superpositions

Wave Optics

Ray Optics

Optical Instruments

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Current and Resistance

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Relativity

The Foundations of Modern Physics

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

Nuclear Physics

Filters

A series of weights connected by very light cords are given an upward acceleration of 4.00 m/s² by a pull P, as shown in the figure. A, B, and C are the tensions in the connecting cords. The SMALLEST of the three tensions, A, B, and C, is closest to

The figure shows two 1.0 kg-blocks connected by a rope. A second rope hangs beneath the lower block. Both ropes have a mass of 250 g. The entire assembly is accelerated upward at 2.3 m/s² by force . What is the tension at the top end of rope 1?