Question 1

You carry a 7.0 kg bag of groceries  above the level floor at a constant velocity of 75 cm/s across a room that is  room.How much work do you do on the bag in the process?

Accepted Answer

Since the bag is being carried at a constant velocity, there is no change in its kinetic energy. Therefore, the work done on the bag is zero.

Question 2

An object is acted upon by a force that represented by the force vs.position graph in the figure.What is the work done as the object moves
(a)from 4 m to 6 m?
(b)from 6 m to 12 m?

Accepted Answer

The answer of An object is acted upon by a...

Question 3

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

Accepted Answer

The answer of Find the net work done by friction...

Question 4

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.

Accepted Answer

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

Question 5

In the figure,two identical ideal massless springs have unstretched lengths of 0.25 m and spring constants of 700 N/m.The springs are attached to a small cube and stretched to a length L of 0.30 m as in Figure A.An external force P pulls the cube a distance D = 0.020 m to the right and holds it there.(See Figure B.)The external force P,that holds the cube in place in Figure B,is closest to

Accepted Answer

The answer of In the figure,two identical ideal massless springs...

Question 6

A spring stretches by  when a  object is attached.What is the weight of a fish that would stretch the spring by

Accepted Answer

The answer of A spring stretches by  when a...

Question 7

Block A (0.40 kg)and block B (0.30 kg)are on a frictionless table (see figure).Spring 1 connects block A to a frictionless peg at 0 and spring 2 connects block A and block B.When the blocks are in uniform circular motion about 0,the springs have lengths of 0.60 m and 0.40 m,as shown.The springs are ideal and massless,and the linear speed of block B is 2.0 m/s.If the spring constant of spring 1 is equal to 30 N/m,the unstretched length of spring 1 is closest to

Accepted Answer

In uniform circular motion, the centripetal force acting on each block is provided by the tension in the springs 
connecting them to the center of the circle.

For block A, we have: 
Tension in spring 1 = kx = mv²/r 
where m is the mass of block A, v is its speed, r is the radius of the circle, k is the spring constant, and x is the 
compression or extension of spring 1.

For block B, we have: 
Tension in spring 2 = 2Tension in spring 1 = 2kx = mv²/r 
where m is the mass of block B and v is its speed.

We can use these equations to find the radius of the circle:

mv²/r = kx 
m(2v)²/r = 2kx

Dividing the second equation by the first one, we get:

4 = 2r/x

r = x/2

Now, we can use the information about the lengths of the springs to find x:

x = sqrt[(0.60 m)² - (0.40 m)²] = 0.48 m

Finally, we can use the equation for tension in spring 1 to find its unstretched length L:

kL = mg 
L = mg/k = (0.40 kg)(9.81 m/s²)/(30 N/m) = 0.52 m

Therefore, the answer is (C) 0.53 m.

Question 8

A force  = 12 N  - 10 N  acts on an object.How much work does this force do as the object moves from the origin to the point

Accepted Answer

The answer of A force  = 12 N ...

Question 9

In the figure,a 700-kg crate is on a rough surface inclined at 30°.A constant external force P = 5600 N is applied horizontally to the crate.As the force pushes the crate a distance of 3.00 m up the incline,the speed changes from 1.40 m/s to 2.50 m/s.How much work does gravity do on the crate during this process?

Accepted Answer

The answer of In the figure,a 700-kg crate is on...

Question 10

An airplane flies 120 km at a constant altitude in a direction 30.0° north of east.A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west.How much work is done on the plane by the air?

Accepted Answer

The work done by the air on the plane can be calculated using the formula $W = Fd\cos(\theta)$, where $F$ is the force, $d$ is the distance, and $\theta$ is the angle between the force direction and the direction of motion. The force is 2.40 kN (2400 N), the distance is 120 km (120,000 m), and the angle between the direction of the force (10° south of west) and the direction of motion (30° north of east) is 180° - (30° + 10°) = 140°. Thus, $W = 2400 \times 120,000 \times \cos(140°)$, which results in a negative value because the angle is greater than 90°, indicating that the work done by the air is in the opposite direction of the motion. The correct calculation leads to a value close to option A.

Question 11

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If  of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

Accepted Answer

The answer of A traveler pulls on a suitcase strap...

Question 12

Block A (0.40 kg)and block B (0.30 kg)are on a frictionless table (see figure).Spring 1 connects block A to a frictionless peg at 0 and spring 2 connects block A and block B.When the blocks are in uniform circular motion about 0,the springs have lengths of 0.60 m and 0.40 m,as shown.The springs are ideal and massless,and the linear speed of block B is 2.0 m/s.If the distance that spring 2 stretches is 0.060 m,the spring constant of spring 2 is closest to

Accepted Answer

The answer of Block A (0.40 kg)and block B (0.30...

Question 13

A force on a particle depends on position such that F(x)= (3.00 N/  )  + (6.00 N/m)x for a particle constrained to move along the x-axis.What work is done by this force on a particle that moves from x = 0.00 m to x = 2.00 m?

Accepted Answer

The answer of A force on a particle depends on...

Question 14

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?

Accepted Answer

The answer of A student slides her 80.0-kg desk across...

Question 15

An object attached to an ideal massless spring is pulled across a frictionless surface.If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at  what is the mass of the object?

Accepted Answer

The answer of An object attached to an ideal massless...

Question 16

In the figure,a constant external force P = 160 N is applied to a 20.0-kg box,which is on a rough horizontal surface.While the force pushes the box a distance of 8.00 m,the speed changes from 0.500 m/s to 2.60 m/s.The work done by friction during this process is closest to

Accepted Answer

The answer of In the figure,a constant external force P...

Question 17

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on the object during a displacement from x = -2.00 m to x = 2.00 m.(Assume an accuracy of 3 significant figures for the numbers
On the graph.)

Accepted Answer

The answer of A graph of the force on an...

Question 18

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m.(Assume an accuracy of 2 significant figures for the numbers on the graph.)

Accepted Answer

The answer of A graph of the force on an...

Question 19

For the vectors shown in the figure,assume numbers are accurate to two significant figures.The scalar product  ×  is closest to

Accepted Answer

The answer of For the vectors shown in the figure,assume...

Question 20

A crane lifts a 425 kg steel beam vertically a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.

Accepted Answer

The answer of A crane lifts a 425 kg steel...

Quiz 9: Work and Kinetic Energy

You carry a 7.0 kg bag of groceries above the level floor at a constant velocity of 75 cm/s across a room that is room.How much work do you do on the bag in the process?

An object is acted upon by a force that represented by the force vs.position graph in the figure.What is the work done as the object moves (a)from 4 m to 6 m? (b)from 6 m to 12 m?

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

A spring stretches by when a object is attached.What is the weight of a fish that would stretch the spring by

A force = 12 N - 10 N acts on an object.How much work does this force do as the object moves from the origin to the point

An airplane flies 120 km at a constant altitude in a direction 30.0° north of east.A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west.How much work is done on the plane by the air?

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

A force on a particle depends on position such that F(x) = (3.00 N/ ) + (6.00 N/m) x for a particle constrained to move along the x-axis.What work is done by this force on a particle that moves from x = 0.00 m to x = 2.00 m?

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?

An object attached to an ideal massless spring is pulled across a frictionless surface.If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at what is the mass of the object?

In the figure,a constant external force P = 160 N is applied to a 20.0-kg box,which is on a rough horizontal surface.While the force pushes the box a distance of 8.00 m,the speed changes from 0.500 m/s to 2.60 m/s.The work done by friction during this process is closest to

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on the object during a displacement from x = -2.00 m to x = 2.00 m.(Assume an accuracy of 3 significant figures for the numbers On the graph.)

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m.(Assume an accuracy of 2 significant figures for the numbers on the graph.)

For the vectors shown in the figure,assume numbers are accurate to two significant figures.The scalar product × is closest to

A crane lifts a 425 kg steel beam vertically a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.

Quiz 9: Work and Kinetic Energy

You carry a 7.0 kg bag of groceries above the level floor at a constant velocity of 75 cm/s across a room that is room.How much work do you do on the bag in the process?

An object is acted upon by a force that represented by the force vs.position graph in the figure.What is the work done as the object moves (a)from 4 m to 6 m? (b)from 6 m to 12 m?

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

A spring stretches by when a object is attached.What is the weight of a fish that would stretch the spring by

A force = 12 N - 10 N acts on an object.How much work does this force do as the object moves from the origin to the point

An airplane flies 120 km at a constant altitude in a direction 30.0° north of east.A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west.How much work is done on the plane by the air?

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

A force on a particle depends on position such that F(x) = (3.00 N/ ) + (6.00 N/m) x for a particle constrained to move along the x-axis.What work is done by this force on a particle that moves from x = 0.00 m to x = 2.00 m?

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?

An object attached to an ideal massless spring is pulled across a frictionless surface.If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at what is the mass of the object?

In the figure,a constant external force P = 160 N is applied to a 20.0-kg box,which is on a rough horizontal surface.While the force pushes the box a distance of 8.00 m,the speed changes from 0.500 m/s to 2.60 m/s.The work done by friction during this process is closest to

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on the object during a displacement from x = -2.00 m to x = 2.00 m.(Assume an accuracy of 3 significant figures for the numbers On the graph.)

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m.(Assume an accuracy of 2 significant figures for the numbers on the graph.)

For the vectors shown in the figure,assume numbers are accurate to two significant figures.The scalar product × is closest to

A crane lifts a 425 kg steel beam vertically a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces.

A crane lifts a 425 kg steel beam vertically a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.