Question 1

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 μ_k = 0.30 between the block and the table.If the 5.0-kg block accelerates downward when it is released,find its acceleration.

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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

We can use the following steps to determine the acceleration of the blocks:
1. Draw a free-body diagram for each block. 
2. Apply Newton's second law in both the x and y directions for each block. 
3. Use the fact that the acceleration of the system is the same for both blocks. 
4. Substitute in values and solve for the acceleration.

Using this method, we find that the acceleration of the blocks is 0.392 m/s^2.

Question 3

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which is parallel to the slope.The coefficient of kinetic friction between the block and the slope is 0.200.What is the magnitude of the acceleration of the block?

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Question 4

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?

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Question 5

Find the net work done by friction on the body of a snake slithering in a complete circle of 3.93 m radius.The coefficient of friction between the ground and the snake is 0.25,and the snake's weight is
54)0 N.

Accepted Answer

The net work done by friction on the body of the snake can be calculated using the formula: 
Work = Force x Distance x cosθ

In this case, the force is the frictional force between the ground and the snake, given by:
F = μN
where μ is the coefficient of friction and N is the normal force, which is equal to the weight of the snake in this case (since it is on a flat surface).

So, 
F = μN = 0.25 x 540 N = 135 N

The distance covered by the snake in one complete circle is equal to its circumference:
C = 2πr = 2π x 3.93 m = 24.68 m

The angle between the force and the displacement (i.e. the angle between the direction of motion and the direction of the frictional force) is 90 degrees, because the force acts perpendicular to the direction of motion. Therefore cosθ = 0.

Putting these values into the formula for work, we get:
Work = 135 N x 24.68 m x 0
Work = 0 J

Since cosθ = 0, the work done by friction on the snake is zero, which means there is no net work done. However, it is important to note that friction does act in the opposite direction to the motion of the snake, which means that it does dissipate energy. This energy is converted into heat, but it is not considered as work done in this context.

Question 6

A system of blocks and a frictionless pulley is shown in the figure.Block A has a mass of 2.0 kg and is on a rough horizontal surface for which μ_s = 0.40 between the surface and block A.The rope pulls horizontally on block A.Block C has a mass of 1.0 kg.An external force P = 23.0 N,applied vertically to block A,maintains the system at rest as shown in the figure.What is the friction force on block A?

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Question 7

A traffic light weighing 100 N is supported by two ropes as shown in the figure. The tensions in the ropes are closest to

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Question 8

The figure shows two forces acting at right angles on an object.They have magnitudes F₁ = 6.3 N and F₂ = 2.1 N. What third force will cause the object to be in equilibrium (acceleration equals zero)?

Accepted Answer

Since the two given forces act at right angles, we can use the Pythagorean theorem to find the resultant force:

F = sqrt[(6.3 N)^2 + (2.1 N)^2] 
F = 6.6 N

To maintain equilibrium, the third force must be equal in magnitude but opposite in direction to the resultant force, so it must also be 6.6 N.

To find the direction, we use trigonometry. The angle between the horizontal and the resultant force can be found as:

theta = arctan(2.1 N / 6.3 N) 
theta = 18.4 degrees

Since the third force must be perpendicular to the resultant force, its angle with the horizontal will be:

90 degrees - 18.4 degrees = 71.6 degrees

However, the question asks for the angle counterclockwise from the first force, which is at an angle of -90 degrees (or 270 degrees) from the horizontal. Therefore, we add 270 degrees to 71.6 degrees to get:

theta = 342.6 degrees

To simplify this answer, we subtract 360 degrees to get an equivalent angle between 0 and 360 degrees:

theta = 342.6 degrees - 360 degrees = -17.4 degrees

Finally, we add 180 degrees to get the counterclockwise angle from the first force:

theta = -17.4 degrees + 180 degrees = 162.6 degrees

Therefore, the answer is A) 6.6 N at 162° counterclockwise from the first force.

Question 9

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope?

Accepted Answer

The force acting on the box down the slope can be calculated as:
F_downslope = m * g * sin(θ) = 6.0 kg * 9.81 m/s^2 * sin(39°) ≈ 37.3 N

The force of kinetic friction can be calculated as:
F_friction = μ * F_norm = μ * m * g * cos(θ) = 0.19 * 6.0 kg * 9.81 m/s^2 * cos(39°) ≈ 22.9 N

The net force acting on the box down the slope is:
F_net = F_downslope - F_friction = 37.3 N - 22.9 N ≈ 14.4 N

The acceleration of the box down the slope can be calculated as:
a = F_net / m = 14.4 N / 6.0 kg ≈ 2.4 m/s^2

Therefore, the rate at which the box accelerates down the slope is:
v = a * t ≈ 2.4 m/s^2 * t

However, the initial velocity of the box is not given, so we cannot determine the rate of acceleration without additional information. Therefore, none of the answer choices are correct.

Question 10

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are μ_s = 0.40 and μ_k = 0.30,respectively.The puck's initial speed is 63 m/s. What vertical height does the puck reach above its starting point?

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Question 11

A box is sliding down an incline tilted at a 12.0° angle above horizontal. The box is initially sliding down the incline at a speed of 1.50 m/s. The coefficient of kinetic friction between the box and the incline is 0.340. How far does the box slide down the incline before coming to rest?

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Question 12

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are μ_s = 0.40 and μ_k = 0.30,respectively.The puck's initial speed is 4.9 m/s.What speed does it have when it slides back down to its starting point?

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Question 13

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed. If the coefficient of kinetic friction between the desk and the floor is 0.400,how much work did she do?

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Question 14

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?

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Question 15

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?

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Question 16

Block A of mass 5.0 kg and block X are attached to a rope which passes over a pulley,as shown in the figure.An 80-N force P is applied horizontally to block A,keeping it in contact with a rough vertical face.The coefficients of static and kinetic friction between the wall and block A are μ_s = 0.40 and μ_k = 0.30.The pulley is light and frictionless.The mass of block X is adjusted until block A moves upward with an acceleration of 1.6 m/s².What is the mass of block X?

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Question 17

Three forces,F₁ = 20.0 N,F₂ = 40.0 N,and F₃ = 10.0 N act on an object with a mass of 2.00 kg which can move along a frictionless inclined plane as shown in the figure.The questions refer to the instant when the object has moved through a distance of 0.600 m along the surface of the inclined plane in the upward direction.Calculate the amount of work done by (a) F₁ (b) F₂ (c) F₃.

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The answer of Three forces,F₁ = 20.0 N,F₂ = 40.0...

Question 18

Two blocks are connected by a string that goes over an ideal pulley as shown in the figure and pulls on block A parallel to the surface of the plane.Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal.The coefficient of static friction between block A and the plane is 0.400.What mass should block B have in order to start block A sliding up the plane?

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Question 19

The figure shows two forces,each of magnitude 4.6 N,acting on an object.The angle between these forces is 40°,and they make equal angles above and below the horizontal.What third force will cause the object to be in equilibrium (acceleration equals zero)?

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Question 20

A 4.00-kg block rests on a 30.0° incline as shown in the figure. If the coefficient of static friction between the block and the incline is 0.700,what magnitude horizontal force F must act on the block to start it moving up the incline?

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Quiz 1: A: Foundations

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which is parallel to the slope.The coefficient of kinetic friction between the block and the slope is 0.200.What is the magnitude of the acceleration of the block?

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?

Find the net work done by friction on the body of a snake slithering in a complete circle of 3.93 m radius.The coefficient of friction between the ground and the snake is 0.25,and the snake's weight is 54) 0 N.

A traffic light weighing 100 N is supported by two ropes as shown in the figure. The tensions in the ropes are closest to

The figure shows two forces acting at right angles on an object.They have magnitudes F₁ = 6.3 N and F₂ = 2.1 N. What third force will cause the object to be in equilibrium (acceleration equals zero) ?

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope?

A box is sliding down an incline tilted at a 12.0° angle above horizontal. The box is initially sliding down the incline at a speed of 1.50 m/s. The coefficient of kinetic friction between the box and the incline is 0.340. How far does the box slide down the incline before coming to rest?

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed. If the coefficient of kinetic friction between the desk and the floor is 0.400,how much work did she do?

The figure shows two forces,each of magnitude 4.6 N,acting on an object.The angle between these forces is 40°,and they make equal angles above and below the horizontal.What third force will cause the object to be in equilibrium (acceleration equals zero) ?

A 4.00-kg block rests on a 30.0° incline as shown in the figure. If the coefficient of static friction between the block and the incline is 0.700,what magnitude horizontal force F must act on the block to start it moving up the incline?

Quiz 1: A: Foundations

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which is parallel to the slope.The coefficient of kinetic friction between the block and the slope is 0.200.What is the magnitude of the acceleration of the block?

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?

Find the net work done by friction on the body of a snake slithering in a complete circle of 3.93 m radius.The coefficient of friction between the ground and the snake is 0.25,and the snake's weight is 54) 0 N.

A traffic light weighing 100 N is supported by two ropes as shown in the figure. The tensions in the ropes are closest to

The figure shows two forces acting at right angles on an object.They have magnitudes F1 = 6.3 N and F2 = 2.1 N. What third force will cause the object to be in equilibrium (acceleration equals zero) ?

A 6.0 kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.19,at what rate does the box accelerate down the slope?

A box is sliding down an incline tilted at a 12.0° angle above horizontal. The box is initially sliding down the incline at a speed of 1.50 m/s. The coefficient of kinetic friction between the box and the incline is 0.340. How far does the box slide down the incline before coming to rest?

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed. If the coefficient of kinetic friction between the desk and the floor is 0.400,how much work did she do?

The figure shows two forces,each of magnitude 4.6 N,acting on an object.The angle between these forces is 40°,and they make equal angles above and below the horizontal.What third force will cause the object to be in equilibrium (acceleration equals zero) ?

A 4.00-kg block rests on a 30.0° incline as shown in the figure. If the coefficient of static friction between the block and the incline is 0.700,what magnitude horizontal force F must act on the block to start it moving up the incline?

The figure shows two forces acting at right angles on an object.They have magnitudes F₁ = 6.3 N and F₂ = 2.1 N. What third force will cause the object to be in equilibrium (acceleration equals zero) ?