Question 1

The work-kinetic energy theorem states that

Accepted Answer

A) work done on an object is converted into kinetic energy and vice versa. 
B) work done on an object comes from the kinetic energy. 
C) work and kinetic energy are the same thing. 
D) work and kinetic energy cannot co-exists at the same time. 
E) none of the above. 
A) work done on an object is converted into kinetic energy and vice versa. 
B) work done on an object comes from the kinetic energy. 
C) work and kinetic energy are the same thing. 
D) work and kinetic energy cannot co-exists at the same time. 
E) none of the above. A

Question 2

Power P is required to lift a body a distance d at a constant speed v.What power is required to lift the body a distance 2d at constant speed 3v?

Accepted Answer

A) P 
B) 2P 
C) 3P 
D) 6P 
E) 3P/2 
A) P 
B) 2P 
C) 3P 
D) 6P 
E) 3P/2 C

Question 3

A force   pushes a block along a horizontal surface against a force of friction   f.If the block undergoes a displacement s at constant velocity,the work done by the resultant force on the block

Accepted Answer

A) is equal to the work done by the force of friction   f 
B) is given by W =   ·   
C) increases the kinetic energy of the block. 
D) increases the potential energy of the block. 
E) is zero. 
A) is equal to the work done by the force of friction   f 
B) is given by W =   ·   
C) increases the kinetic energy of the block. 
D) increases the potential energy of the block. 
E) is zero. E

Question 4

To maintain an automobile in approximately constant acceleration,its engine must develop power that increases with time.Suppose that in one situation the work done by an engine is given by   where the units are SI.The power developed by this engine at t = 2 s is

Accepted Answer

A) 3.4 $\times$ 104 W 
B) 6.8 $\times$ 104 W 
C) 1.0 $\times$ 105 W 
D) 2.1 $\times$ 105 W 
E) 3.0 $\times$ 105 W 
A) 3.4 $\times$ 104 W 
B) 6.8 $\times$ 104 W 
C) 1.0 $\times$ 105 W 
D) 2.1 $\times$ 105 W 
E) 3.0 $\times$ 105 W

Question 5

The angle between the vector   =   + 2   + 3   and the y axis is approximately

Accepted Answer

A) 58º 
B) 75º 
C) 17º 
D) 26º 
E) 37º 
A) 58º 
B) 75º 
C) 17º 
D) 26º 
E) 37º

Question 6

Use the figure for the question. The graph shows the speed of a light truck of mass 4000 kg coasting on neutral down a level straight road.The truck is slowing down due to air resistance and rolling friction.  
-Estimate the work done per second by the retarding force at t = 5s.

Accepted Answer

A)    20 kJ 
B)    40 kJ 
C)    60 kJ 
D)    80 kJ 
E)    100 kJ 
A)    20 kJ 
B)    40 kJ 
C)    60 kJ 
D)    80 kJ 
E)    100 kJ

Question 7

What is the difference in work needed to push a 100 kg crate (at constant speed)a distance of 2 m along an inclined plane that is at an angle of 20 degrees with the horizontal,if the coefficient of kinetic friction was equal to 0.20 or zero?

Accepted Answer

A) 670 N 
B) 1040 N 
C) no difference 
D) 370 N 
E) 134 N 
A) 670 N 
B) 1040 N 
C) no difference 
D) 370 N 
E) 134 N

Question 8

In a television tube,an electron starting from rest experiences a force of 4.0 $\times$ 10-15 N over a distance of 50 cm.The final speed of the electron is (do not worry about relativistic effects):

Accepted Answer

A) 4.4 $\times$ 1015 m/s 
B) 6.6 $\times$ 107 m/s 
C) 3.3 $\times$ 107 m/s 
D) 1.3 $\times$ 108 m/s 
E) 6.6 $\times$ 108 m/s 
A) 4.4 $\times$ 1015 m/s 
B) 6.6 $\times$ 107 m/s 
C) 3.3 $\times$ 107 m/s 
D) 1.3 $\times$ 108 m/s 
E) 6.6 $\times$ 108 m/s

Question 9

The angle between the vectors   = -2   + 3   and   = 4   - 5   is approximately

Accepted Answer

A) 5º 
B) 47º 
C) 175º 
D) 15º 
E) 26º 
A) 5º 
B) 47º 
C) 175º 
D) 15º 
E) 26º

Question 10

A force   acts on a body and produces an acceleration   .The body undergoes a displacement   and attains a velocity   in time t.The instantaneous power being developed at time t is given by

Accepted Answer

A)    ·   
B)    ·   at2  
C)    ·   
D) (   · 2   )/t2  
E)    ·   
A)    ·   
B)    ·   at2  
C)    ·   
D) (   · 2   )/t2  
E)    ·

Question 11

Kids love to crash their toy cars together.One such collision involves a 0.5 kg car moving at 0.3 m/s colliding with a stationary toy car of mass 0.3 kg.The two toys stick together and move away from the collision point at 0.188 m/s.By what factor is the initial kinetic energy greater than the final kinetic energy?

Accepted Answer

A) 0.63 
B) 1.6 
C) 2.5 
D) 4.2 
E) 1.0 The kinetic energy stays the same. 
A) 0.63 
B) 1.6 
C) 2.5 
D) 4.2 
E) 1.0 The kinetic energy stays the same.

Question 12

The power developed by a certain engine is a function of time according to   where the units are SI.The work done by the engine in the interval from t = 0 to t = 2 s is

Accepted Answer

A) 9 J 
B) 10 J 
C) 14 J 
D) 16 J 
E) 18 J 
A) 9 J 
B) 10 J 
C) 14 J 
D) 16 J 
E) 18 J

Question 13

The work expended to accelerate a car from 0 to 30 m/s

Accepted Answer

A) is more than that required to accelerate it from 30 m/s to 60 m/s. 
B) is equal to that required to accelerate it from 30 m/s to 60 m/s. 
C) is less than that required to accelerate it from 30 m/s to 60 m/s. 
D) can be any of the preceding,depending on the time taken. 
E) is described by none of these statements. 
A) is more than that required to accelerate it from 30 m/s to 60 m/s. 
B) is equal to that required to accelerate it from 30 m/s to 60 m/s. 
C) is less than that required to accelerate it from 30 m/s to 60 m/s. 
D) can be any of the preceding,depending on the time taken. 
E) is described by none of these statements.

Question 14

A motorcycle of mass m starting from rest can attain a speed v after work W is performed by its engine.If the engine could perform work 4W then the final speed would be?

Accepted Answer

A) 4v 
B) 2v 
C) 16v 
D) (2v)1/2  
E) (4v)1/2  
A) 4v 
B) 2v 
C) 16v 
D) (2v)1/2  
E) (4v)1/2

Question 15

If mechanical work is done on a body,the body must

Accepted Answer

A) accelerate. 
B) be in equilibrium. 
C) not exert any force. 
D) have no friction force exerted on it. 
E) move. 
A) accelerate. 
B) be in equilibrium. 
C) not exert any force. 
D) have no friction force exerted on it. 
E) move.

Question 16

The angle between the vector   =   + 2   + 3k and the x axis is approximately

Accepted Answer

A) 17º 
B) 26º 
C) 37º 
D) 58º 
E) 75º 
A) 17º 
B) 26º 
C) 37º 
D) 58º 
E) 75º

Question 17

What minimum power rating must a water pump have if needs to raise water at 20 kg per minute from a depth of 9 m?

Accepted Answer

A) 1.76 kW 
B) 29.4 W 
C) 106 kW 
D) 3.0 W 
E) 180 W 
A) 1.76 kW 
B) 29.4 W 
C) 106 kW 
D) 3.0 W 
E) 180 W

Question 18

Determine which of the following statements is correct.

Accepted Answer

A) The scalar product of two vectors can be negative. 
B)    where c is a constant. 
C) The scalar product can be non-zero even if two of the three components of the two vectors are equal to zero. 
D) If   then   . 
E) All the above statements are correct. 
A) The scalar product of two vectors can be negative. 
B)    where c is a constant. 
C) The scalar product can be non-zero even if two of the three components of the two vectors are equal to zero. 
D) If   then   . 
E) All the above statements are correct.

Question 19

Two skiers start at the same place and finish at the same place.Skier A takes a straight,smooth route to the finish whereas Skier B takes a curvy,bumpy route to the finish.If you assume that friction is negligible,which of the following statements is true?

Accepted Answer

A) Skier A has the same speed as skier B at the finish. 
B) Skier B has the greater speed at the finish. 
C) Skier A has the greater speed at the finish because the route is straight. 
D) Skier A has the greater speed at the finish because the route is smooth. 
E) Skier A has the greater speed at the finish because the route is both straight and smooth. 
A) Skier A has the same speed as skier B at the finish. 
B) Skier B has the greater speed at the finish. 
C) Skier A has the greater speed at the finish because the route is straight. 
D) Skier A has the greater speed at the finish because the route is smooth. 
E) Skier A has the greater speed at the finish because the route is both straight and smooth.

Question 20

If the average power output of a car engine is the same as a 100-W light bulb,how long would it take a 1200-kg car to go from zero to 96 km/h (60 mph)?

Accepted Answer

A) 8.5 $\times$ 103 s 
B) 5.5 $\times$ 104 s 
C) 65 s 
D) 160 s 
E) 4.3 $\times$ 103 s 
A) 8.5 $\times$ 103 s 
B) 5.5 $\times$ 104 s 
C) 65 s 
D) 160 s 
E) 4.3 $\times$ 103 s

Exam 6: Work and Energy

The work-kinetic energy theorem states that

Power P is required to lift a body a distance d at a constant speed v.What power is required to lift the body a distance 2d at constant speed 3v?

A force pushes a block along a horizontal surface against a force of friction f.If the block undergoes a displacement s at constant velocity,the work done by the resultant force on the block

To maintain an automobile in approximately constant acceleration,its engine must develop power that increases with time.Suppose that in one situation the work done by an engine is given by where the units are SI.The power developed by this engine at t = 2 s is

The angle between the vector = + 2 + 3 and the y axis is approximately

Use the figure for the question. The graph shows the speed of a light truck of mass 4000 kg coasting on neutral down a level straight road.The truck is slowing down due to air resistance and rolling friction. -Estimate the work done per second by the retarding force at t = 5s.

What is the difference in work needed to push a 100 kg crate (at constant speed)a distance of 2 m along an inclined plane that is at an angle of 20 degrees with the horizontal,if the coefficient of kinetic friction was equal to 0.20 or zero?

In a television tube,an electron starting from rest experiences a force of 4.0 ×\times× 10-15 N over a distance of 50 cm.The final speed of the electron is (do not worry about relativistic effects):

The angle between the vectors = -2 + 3 and = 4 - 5 is approximately

A force acts on a body and produces an acceleration .The body undergoes a displacement and attains a velocity in time t.The instantaneous power being developed at time t is given by

The power developed by a certain engine is a function of time according to where the units are SI.The work done by the engine in the interval from t = 0 to t = 2 s is

The work expended to accelerate a car from 0 to 30 m/s

A motorcycle of mass m starting from rest can attain a speed v after work W is performed by its engine.If the engine could perform work 4W then the final speed would be?

If mechanical work is done on a body,the body must

The angle between the vector = + 2 + 3k and the x axis is approximately

What minimum power rating must a water pump have if needs to raise water at 20 kg per minute from a depth of 9 m?

Determine which of the following statements is correct.

Two skiers start at the same place and finish at the same place.Skier A takes a straight,smooth route to the finish whereas Skier B takes a curvy,bumpy route to the finish.If you assume that friction is negligible,which of the following statements is true?

If the average power output of a car engine is the same as a 100-W light bulb,how long would it take a 1200-kg car to go from zero to 96 km/h (60 mph)?

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

A force pushes a block along a horizontal surface against a force of friction _f.If the block undergoes a displacement s at constant velocity,the work done by the resultant force on the block

In a television tube,an electron starting from rest experiences a force of 4.0 $\times$ 10^-15N over a distance of 50 cm.The final speed of the electron is (do not worry about relativistic effects):