Question 1

Force and potential energy: A potential energy function is given by U(x) = (3.00 N/m)x - (1.00 N/m3)x3. At what position or positions is the force equal to zero?

Accepted Answer

A)    m and -
  m 
B)  0.00 m,   m and -
  m 
C)  1.00 m and -1.00 m 
D)  3.00 m and -3.00 m 
E)  The force is not zero at any location. 
A)    m and -
  m 
B)  0.00 m,   m and -
  m 
C)  1.00 m and -1.00 m 
D)  3.00 m and -3.00 m 
E)  The force is not zero at any location.

Question 2

Work: 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

A)  -1040 J 
B)  +1110 J 
C)  +1170 J 
D)  +1040 J 
E)  -1170 J 
A)  -1040 J 
B)  +1110 J 
C)  +1170 J 
D)  +1040 J 
E)  -1170 J

Question 3

Force and potential energy: A potential energy function is given by U(x) = (3.00 J/m)x + (1.00 J/m3)x3. What is the force function F(x) that is associated with this potential energy function?

Accepted Answer

F(x) = -3.

Question 4

Hooke's law: Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched?

Accepted Answer

A)  Graph a 
B)  Graph b 
C)  Graph c 
D)  Graph d 
A)  Graph a 
B)  Graph b 
C)  Graph c 
D)  Graph d

Question 5

Kinetic energy: The coefficient of the restitution of an object is defined as the ratio of its outgoing to incoming speed when the object collides with a rigid surface. For an object with a coefficient of 0.78, what fraction of the object's kinetic energy is lost during a single collision?

Accepted Answer

A)  39% 
B)  16% 
C)  47% 
D)  61% 
A)  39% 
B)  16% 
C)  47% 
D)  61%

Question 6

Work-energy theorem: Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground

Accepted Answer

A)  both of them will have the same kinetic energy. 
B)  the heavier one will have twice the kinetic energy of the lighter one. 
C)  the heavier one will have four times the kinetic energy of the lighter one. 
D)  the heavier one will have   times the kinetic energy of the lighter one. 
A)  both of them will have the same kinetic energy. 
B)  the heavier one will have twice the kinetic energy of the lighter one. 
C)  the heavier one will have four times the kinetic energy of the lighter one. 
D)  the heavier one will have   times the kinetic energy of the lighter one.

Question 7

Force and potential energy: The only force acting on an object moving along the x-axis is the conservative force given by F(x) = (2.00 N/m)x + (1.00 N/m3)x3.
(a) What is the change in potential energy when the object moves from x = 1.00 m to x = 2.00 m?
(b) What is the change in kinetic energy when the object moves from x = 1.00 m to x = 2.00 m?

Accepted Answer

(a) -6.75

Question 8

Energy conservation with conservative forces: In the figure, a stunt car driver negotiates the frictionless track shown in such a way that the car is barely in contact with the track at the top of the loop. The radius of the track is 9.9 m and the mass of the car is 1800 kg. Find the magnitude of the force of the car on the track when the car is at point A. You can treat the car as a point mass.

Accepted Answer

The answer of Energy conservation with conservative forces: In the...

Question 9

Force and potential energy: A force on an object is given by F(x) = (-4.00 N/m)x + ( 2.00 N/m3)x3. What is the change in potential energy in moving from x = 1.00 m to x = 2.00 m?

Accepted Answer

A)  10.0 J 
B)  -1.50 J 
C)  -10.0 J 
D)  1.50 J 
E)  12.0 J 
A)  10.0 J 
B)  -1.50 J 
C)  -10.0 J 
D)  1.50 J 
E)  12.0 J

Exam 6: Work and Kinetic Energy

Force and potential energy: A potential energy function is given by U(x) = (3.00 N/m)x - (1.00 N/m3)x3. At what position or positions is the force equal to zero?

Work: 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

Force and potential energy: A potential energy function is given by U(x) = (3.00 J/m)x + (1.00 J/m3)x3. What is the force function F(x) that is associated with this potential energy function?

Hooke's law: Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched?

Kinetic energy: The coefficient of the restitution of an object is defined as the ratio of its outgoing to incoming speed when the object collides with a rigid surface. For an object with a coefficient of 0.78, what fraction of the object's kinetic energy is lost during a single collision?

Work-energy theorem: Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground

Force and potential energy: A force on an object is given by F(x) = (-4.00 N/m)x + ( 2.00 N/m3)x3. What is the change in potential energy in moving from x = 1.00 m to x = 2.00 m?

Motion Along a Straight Line

Motion in Two or Three Dimensions

Newtons Laws of Motion

Applying Newtons Laws

Potential Energy and Energy Conservation

Momentum, Impulse, and Collisions

Rotation of Rigid Bodies

Dynamics of Rotational Motion

Equilibrium and Elasticity

Fluid Mechanics

Gravitation

Periodic Motion

Mechanical Waves

Sound and Hearing

Temperature and Heat

Thermal Properties of Matter

The First Law of Thermodynamics

The Second Law of Thermodynamics

Electric Charge and Electric Field

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current, Resistance, and Electromotive Force

Direct-Current Circuits

Magnetic Field and Magnetic Forces

Sources of Magnetic Field

Electromagnetic Induction

Inductance

Alternating Current

Electromagnetic Waves Optics

The Nature and Propagation of Light

Geometric Optics

Interference

Filters

Force and potential energy: A potential energy function is given by U(x) = (3.00 N/m)x - (1.00 N/m³)x³. At what position or positions is the force equal to zero?

Force and potential energy: A potential energy function is given by U(x) = (3.00 J/m)x + (1.00 J/m³)x³. What is the force function F(x) that is associated with this potential energy function?

Force and potential energy: A force on an object is given by F(x) = (-4.00 N/m)x + ( 2.00 N/m³)x³. What is the change in potential energy in moving from x = 1.00 m to x = 2.00 m?