Question 1

A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring

Accepted Answer

A

Question 2

A spring stretches by 21.0 cm when a 135 N object is attached. What is the weight of a fish that would stretch the spring by 31 cm?

Accepted Answer

A

Question 3

In the figure, two identical springs have unstretched lengths of 0.25 m and spring constants of 300 N/m. The springs are attached to a small cube and stretched to a length L of 0.36 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 work done by the external force P in pulling the cube 0.020 m is closest to

Accepted Answer

A

Question 4

Is it possible for a system to have negative potential energy?

Accepted Answer

The zero of potential energy is arbitrary, meaning that it can be defined at any point. Therefore, it is possible for a system to have negative potential energy with respect to a different choice of zero.

Question 5

In a perfectly ELASTIC collision between two perfectly rigid objects

Accepted Answer

In a perfectly elastic collision between two perfectly rigid objects, both the momentum and the kinetic energy of the system are conserved. This means that the total momentum of the system before the collision is equal to the total momentum of the system after the collision, and the total kinetic energy of the system before the collision is equal to the total kinetic energy of the system after the collision. This is because in a perfectly elastic collision, there is no loss of kinetic energy due to deformation or friction, and the objects bounce off each other with no loss of energy.

Question 6

A force F = bx³ acts in the x direction, where the value of b is 3.7 N/m³. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

Accepted Answer

The work done by a variable force is given by the integral of the force over the distance. Here, W = ∫(from 0 to 2.6) bx^3 dx = [b/4 * x^4] from 0 to 2.6. Substituting b = 3.7 N/m^3, we get W = (3.7/4) * (2.6^4) = 42 J.

Question 7

A person pushes horizontally on a heavy box and slides it across the level floor at constant velocity. The person pushes with a 60.0 N force for the first 6.88 m, at which time he begins to tire. The force he exerts then starts to decrease linearly from 60.0 N to 0.00 N across the remaining 6.88 m. How much total work did the person do on the box?

Accepted Answer

Work done in pushing the box with a constant force for the first 6.88 m:
W1 = F1 * d1 = 60.0 N * 6.88 m = 413 J

Work done in pushing the box with a varying force for the remaining 6.88 m:
The average force over the 2nd half of the distance is (60.0 + 0.00)/2 = 30.0 N.

Work done:
W2 = Favg * d2 = 30.0 N * 6.88 m = 206 J

Total work done is the sum of W1 and W2:
W = W1 + W2 = 413 J + 206 J = 619 J

Therefore, the best choice is A) 619 J.

Question 8

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 2.0 m/s², what is the mass of the object?

Accepted Answer

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

Question 9

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...

Question 10

Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force  to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water?

Accepted Answer

According to the conservation of momentum, the total momentum of the system before and after the push must be equal. Since Jacques pushed George's canoe in one direction, an equal and opposite momentum must be imparted to Jacques' canoe. Therefore, the final momentum is in the direction opposite of the force applied. However, since the canoes come to a complete stop, the final kinetic energy is zero.

Question 11

A force on a particle depends on position such that F(x) = (3.00 N/m²)x² + (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 12

It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring?

Accepted Answer

The answer of It requires 49 J of work to...

Question 13

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

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

Question 14

A shell explodes into two fragments, one fragment 25 times heavier than the other. If any gas from the explosion has negligible mass, then

Accepted Answer

The law of conservation of momentum states that the total momentum of a closed system is constant if no external forces act on it. In the case of the shell explosion, the system is the two fragments. Since they are part of the same system and no external forces are considered, the momentum change of one fragment must be equal and opposite to the momentum change of the other, regardless of their masses. This means the momentum change of the lighter fragment is exactly the same as the momentum change of the heavier fragment, but in the opposite direction.

Question 15

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...

Question 16

Which of the graphs in the figure illustrates Hooke's Law?

Accepted Answer

The answer of Which of the graphs in the figure...

Question 17

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction?

Accepted Answer

The answer of On a smooth horizontal floor, an object...

Question 18

In an INELASTIC collision between two objects

Accepted Answer

In an inelastic collision, the momentum of the system is conserved, but the kinetic energy of the system is not conserved. This is because some of the kinetic energy is transformed into other forms of energy, such as heat or sound, during the collision. Therefore, choices A, B, D, and E are all incorrect.

Question 19

A baseball is thrown vertically upward and feels no air resistance. As it is rising

Accepted Answer

As the baseball is thrown vertically upward, its momentum changes direction, making it not conserved. However, since no external forces act on the baseball (i.e., no air resistance or friction), the mechanical energy of the system (baseball and Earth) remains constant. Therefore, option B is the correct answer.

Question 20

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be

Accepted Answer

The slope of the displacement vs. applied force plot for an ideal elastic spring is the reciprocal of the spring constant, according to Hooke's Law (F = kx), where k is the spring constant.

Quiz 10: Energy

A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring

A spring stretches by 21.0 cm when a 135 N object is attached. What is the weight of a fish that would stretch the spring by 31 cm?

Is it possible for a system to have negative potential energy?

In a perfectly ELASTIC collision between two perfectly rigid objects

A force F = bx³ acts in the x direction, where the value of b is 3.7 N/m³. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

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 2.0 m/s², what is the mass of the object?

A force on a particle depends on position such that F(x) = (3.00 N/m²) x² + (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?

It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring?

A shell explodes into two fragments, one fragment 25 times heavier than the other. If any gas from the explosion has negligible mass, then

Which of the graphs in the figure illustrates Hooke's Law?

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction?

In an INELASTIC collision between two objects

A baseball is thrown vertically upward and feels no air resistance. As it is rising

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be

Quiz 10: Energy

A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring

A spring stretches by 21.0 cm when a 135 N object is attached. What is the weight of a fish that would stretch the spring by 31 cm?

Is it possible for a system to have negative potential energy?

In a perfectly ELASTIC collision between two perfectly rigid objects

A force F = bx3 acts in the x direction, where the value of b is 3.7 N/m3. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

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 2.0 m/s2, what is the mass of the object?

A force on a particle depends on position such that F(x) = (3.00 N/m2) x2 + (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?

It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring?

A shell explodes into two fragments, one fragment 25 times heavier than the other. If any gas from the explosion has negligible mass, then

Which of the graphs in the figure illustrates Hooke's Law?

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction?

In an INELASTIC collision between two objects

A baseball is thrown vertically upward and feels no air resistance. As it is rising

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be

A force F = bx³ acts in the x direction, where the value of b is 3.7 N/m³. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

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 2.0 m/s², what is the mass of the object?

A force on a particle depends on position such that F(x) = (3.00 N/m²) x² + (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?