Question 1

The work done by a crane lifting a boat is plotted on the graph. The power developed by the crane when t = 1.5 s is

Accepted Answer

A)  40 W 
B)  20 W 
C)  10 W 
D)  27 W 
E)  30 W 
A)  40 W 
B)  20 W 
C)  10 W 
D)  27 W 
E)  30 W B

Question 2

A 5-kg object undergoes a displacement $\Delta$  
= 2   + 3   . During the displacement, a constant force   = 4   - 2   acts on the object. All values are given in SI units. The work done by the force   on this object is

Accepted Answer

A)  8 J 
B)  -6 J 
C)  2 J 
D)  14 J 
E)  -2 J 
A)  8 J 
B)  -6 J 
C)  2 J 
D)  14 J 
E)  -2 J C

Question 3

A 50% efficient hydroelectric power plant generates electricity from water falling a height of 110 m and at a rate of x kg/s. If the maximum possible power output of the plant was 27.0 MW, what is x?

Accepted Answer

A)  25,000 kg/s 
B)  50,000 kg/s 
C)  100,000 kg/s 
D)  5100 kg/s 
E)  510,000 kg/s 
A)  25,000 kg/s 
B)  50,000 kg/s 
C)  100,000 kg/s 
D)  5100 kg/s 
E)  510,000 kg/s B

Question 4

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 5

A body is acted upon by a force of 10 N and undergoes a displacement in the direction of the force in accordance with the relation s = 3t2 + 2t, where s is the displacement in meters and t is in seconds. The rate at which the force is doing work at the instant t = 2 s is

Accepted Answer

A)  14 W 
B)  12 W 
C)  120 W 
D)  140 W 
E)  160 W 
A)  14 W 
B)  12 W 
C)  120 W 
D)  140 W 
E)  160 W

Question 6

A 6.0-kg block slides from rest at position A down a frictionless incline to position B. The speed of the block at B is

Accepted Answer

A)  3.1 m/s 
B)  4.4 m/s 
C)  11 m/s 
D)  1.8 m/s 
E)  20 m/s 
A)  3.1 m/s 
B)  4.4 m/s 
C)  11 m/s 
D)  1.8 m/s 
E)  20 m/s

Question 7

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
W = 7000t2 + 40,000t + 100,000
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 8

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 9

Use the figure to answer the next question. A light rope runs through two frictionless pulleys of negligible mass. A mass, m, is hung from one of the pulleys and a force, F is applied to one end of the rope so that the mass moves at a constant speed.  
-What is the force needed to move the mass at a constant speed?

Accepted Answer

A)  0 
B)    mg 
C)  mg 
D)  2mg 
E)  4mg 
A)  0 
B)    mg 
C)  mg 
D)  2mg 
E)  4mg

Question 10

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 11

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 12

An object of mass, m, is placed in an arc of a circle of radius, r. The coefficient of kinetic friction between the object and the surface of the arc is $\mu$k. What is the work done by friction in going from P1 and P2?

Accepted Answer

A)  -$\mu$ kmg r (cos($\theta$2)-cos($\theta$1)) 
B)  -$\mu$kmg r (sin($\theta$2)-sin($\theta$1)) 
C)  -$\mu$kmg r cos($\theta$2) sin($\theta$1) 
D)  -$\mu$kmg r sin(F$\theta$2)cos($\theta$1) 
E)  none of the above 
A)  -$\mu$ kmg r (cos($\theta$2)-cos($\theta$1)) 
B)  -$\mu$kmg r (sin($\theta$2)-sin($\theta$1)) 
C)  -$\mu$kmg r cos($\theta$2) sin($\theta$1) 
D)  -$\mu$kmg r sin(F$\theta$2)cos($\theta$1) 
E)  none of the above

Question 13

The graph represents the force acting on a body plotted against the displacement of the body in the direction of the force. The total work done by the force from x = 0 to x = x is

Accepted Answer

A)  m 
B)  mx2 + b 
C)    ·mx2 + b 
D)  mx + b 
E)    ·mx2 + bx 
A)  m 
B)  mx2 + b 
C)    ·mx2 + b 
D)  mx + b 
E)    ·mx2 + bx

Question 14

The kinetic energy of a car is 1.00 $\times$ 105 J. If the car's speed is increased by
20 percent, the kinetic energy of the car becomes

Accepted Answer

A)  4.00 $\times$ 103 J 
B)  1.20 $\times$ 105 J 
C)  1.44 $\times$ 105 J 
D)  1.04 $\times$ 105 J 
E)  unknown; the answer depends on the mass of the car, which is not given 
A)  4.00 $\times$ 103 J 
B)  1.20 $\times$ 105 J 
C)  1.44 $\times$ 105 J 
D)  1.04 $\times$ 105 J 
E)  unknown; the answer depends on the mass of the car, which is not given

Question 15

A donkey is attached by a rope to a wooden cart at an angle of 23S1U1P1$\circ$S1S1P0 to the horizontal. The tension in the rope is 210 N. If the cart is dragged horizontally along the floor with a constant speed of 6 km/h, calculate how much work the donkey does in 35 minutes.

Accepted Answer

A)  740 kJ 
B)  290 kJ 
C)  680 kJ 
D)  11 kJ 
E)  0.70 kJ 
A)  740 kJ 
B)  290 kJ 
C)  680 kJ 
D)  11 kJ 
E)  0.70 kJ

Question 16

A motor is lifting a mass of 35.0 kg at a constant speed of 6.00 m/s. If friction is neglected, the power developed by the motor to do this lifting is

Accepted Answer

A)  740 W 
B)  1.5 $\times$ 103 W 
C)  2.1 $\times$ 103 W 
D)  59 W 
E)  43 W 
A)  740 W 
B)  1.5 $\times$ 103 W 
C)  2.1 $\times$ 103 W 
D)  59 W 
E)  43 W

Question 17

Initially a body moves in one direction and has kinetic energy K. Then it moves in the opposite direction with three times its initial speed. What is the kinetic energy now?

Accepted Answer

A)  K 
B)  3K 
C)  -3K 
D)  9K 
E)  -9K 
A)  K 
B)  3K 
C)  -3K 
D)  9K 
E)  -9K

Question 18

In pushing a load, a woman exerts a force as given by the graph. What was the total work done by the woman?

Accepted Answer

A)  400 J 
B)  200 J 
C)  2000 J 
D)  1000 J 
E)  500 J 
A)  400 J 
B)  200 J 
C)  2000 J 
D)  1000 J 
E)  500 J

Question 19

A variable force is represented on an F-versus-x graph. Which of the following is the work done by this force?

Accepted Answer

A)  the slope of the curve 
B)  the area bounded by the curve and the x axis 
C)  the area bounded by the curve and the F axis 
D)  the F value multiplied by the x value 
E)  the F value divided by the x value 
A)  the slope of the curve 
B)  the area bounded by the curve and the x axis 
C)  the area bounded by the curve and the F axis 
D)  the F value multiplied by the x value 
E)  the F value divided by the x value

Question 20

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.

The work done by a crane lifting a boat is plotted on the graph. The power developed by the crane when t = 1.5 s is

A 50% efficient hydroelectric power plant generates electricity from water falling a height of 110 m and at a rate of x kg/s. If the maximum possible power output of the plant was 27.0 MW, what is x?

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?

A body is acted upon by a force of 10 N and undergoes a displacement in the direction of the force in accordance with the relation s = 3t² + 2t, where s is the displacement in meters and t is in seconds. The rate at which the force is doing work at the instant t = 2 s is

A 6.0-kg block slides from rest at position A down a frictionless incline to position B. The speed of the block at B is

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 W = 7000t² + 40,000t + 100,000 Where the units are SI. The power developed by this engine at t = 2 s is

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?

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

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?

The graph represents the force acting on a body plotted against the displacement of the body in the direction of the force. The total work done by the force from x = 0 to x = x is

The kinetic energy of a car is 1.00 $\times$ 10⁵ J. If the car's speed is increased by 20 percent, the kinetic energy of the car becomes

A donkey is attached by a rope to a wooden cart at an angle of 23^$\circ$ to the horizontal. The tension in the rope is 210 N. If the cart is dragged horizontally along the floor with a constant speed of 6 km/h, calculate how much work the donkey does in 35 minutes.

A motor is lifting a mass of 35.0 kg at a constant speed of 6.00 m/s. If friction is neglected, the power developed by the motor to do this lifting is

Initially a body moves in one direction and has kinetic energy K. Then it moves in the opposite direction with three times its initial speed. What is the kinetic energy now?

In pushing a load, a woman exerts a force as given by the graph. What was the total work done by the woman?

A variable force is represented on an F-versus-x graph. Which of the following is the work done by this force?

Determine which of the following statements is correct.

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

Filters

Exam 6: Work and Energy

The work done by a crane lifting a boat is plotted on the graph. The power developed by the crane when t = 1.5 s is

A 5-kg object undergoes a displacement Δ\DeltaΔ = 2 + 3 . During the displacement, a constant force = 4 - 2 acts on the object. All values are given in SI units. The work done by the force on this object is

A 50% efficient hydroelectric power plant generates electricity from water falling a height of 110 m and at a rate of x kg/s. If the maximum possible power output of the plant was 27.0 MW, what is x?

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?

A body is acted upon by a force of 10 N and undergoes a displacement in the direction of the force in accordance with the relation s = 3t2 + 2t, where s is the displacement in meters and t is in seconds. The rate at which the force is doing work at the instant t = 2 s is

A 6.0-kg block slides from rest at position A down a frictionless incline to position B. The speed of the block at B is

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 W = 7000t2 + 40,000t + 100,000 Where the units are SI. The power developed by this engine at t = 2 s is

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?

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

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?

An object of mass, m, is placed in an arc of a circle of radius, r. The coefficient of kinetic friction between the object and the surface of the arc is μ\muμ k. What is the work done by friction in going from P1 and P2?

The graph represents the force acting on a body plotted against the displacement of the body in the direction of the force. The total work done by the force from x = 0 to x = x is

The kinetic energy of a car is 1.00 ×\times× 105 J. If the car's speed is increased by 20 percent, the kinetic energy of the car becomes

A donkey is attached by a rope to a wooden cart at an angle of 23 ∘\circ∘ to the horizontal. The tension in the rope is 210 N. If the cart is dragged horizontally along the floor with a constant speed of 6 km/h, calculate how much work the donkey does in 35 minutes.

A motor is lifting a mass of 35.0 kg at a constant speed of 6.00 m/s. If friction is neglected, the power developed by the motor to do this lifting is

Initially a body moves in one direction and has kinetic energy K. Then it moves in the opposite direction with three times its initial speed. What is the kinetic energy now?

In pushing a load, a woman exerts a force as given by the graph. What was the total work done by the woman?

A variable force is represented on an F-versus-x graph. Which of the following is the work done by this force?

Determine which of the following statements is correct.

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

Filters

A body is acted upon by a force of 10 N and undergoes a displacement in the direction of the force in accordance with the relation s = 3t² + 2t, where s is the displacement in meters and t is in seconds. The rate at which the force is doing work at the instant t = 2 s is

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 W = 7000t² + 40,000t + 100,000 Where the units are SI. The power developed by this engine at t = 2 s is

The kinetic energy of a car is 1.00 $\times$ 10⁵ J. If the car's speed is increased by 20 percent, the kinetic energy of the car becomes

A donkey is attached by a rope to a wooden cart at an angle of 23^$\circ$ to the horizontal. The tension in the rope is 210 N. If the cart is dragged horizontally along the floor with a constant speed of 6 km/h, calculate how much work the donkey does in 35 minutes.