Question 1

The force combination that forms a simple couple is

Accepted Answer

A)    and   
B)    and   
C)    and   
D)    and   
E)    and   
A)    and   
B)    and   
C)    and   
D)    and   
E)    and

Question 2

Which of the following could not have units of N/m2?

Accepted Answer

A)  Young's modulus 
B)  shear modulus 
C)  bulk modulus 
D)  stress 
E)  strain 
A)  Young's modulus 
B)  shear modulus 
C)  bulk modulus 
D)  stress 
E)  strain

Question 3

A 3-m long wire with a diameter of 1.5 mm has a Young's modulus of 9 $\times$ 1010 N/m2. What mass hung from the wire would extend it by 3 mm?

Accepted Answer

A)  159 kg 
B)  5.20 kg 
C)  16.2 kg 
D)  64.8 kg 
E)  None of the above 
A)  159 kg 
B)  5.20 kg 
C)  16.2 kg 
D)  64.8 kg 
E)  None of the above

Question 4

Four happy kids are lining up and jumping off a diving board one after another. The kids, each with a mass of 40 kg, are situated as in the above figure, and the uniform board has a total mass of 60 kg. Calculate the force on the support closest to the water.

Accepted Answer

A)  3140 N, up 
B)  4320 N, down 
C)  4320 N, up 
D)  3140 N, down 
E)  3920 N, down 
A)  3140 N, up 
B)  4320 N, down 
C)  4320 N, up 
D)  3140 N, down 
E)  3920 N, down

Question 5

A design project requires you to construct a crane to lift a maximum of 5000 kg and with a maximum upward acceleration of 2 m/s2, and with a safety factor of 5. If the cable is
20m long, by how much does the cable stretch when the crane is operating at the design limits?

Accepted Answer

A)  2.80 cm 
B)  1.05 cm 
C)  6.21 cm 
D)  0.84 cm 
E)  5.22 cm 
A)  2.80 cm 
B)  1.05 cm 
C)  6.21 cm 
D)  0.84 cm 
E)  5.22 cm

Question 6

An upright refrigerator tips over if its

Accepted Answer

A)  height is greater than its width. 
B)  center of mass is below its middle. 
C)  center of mass is above its middle. 
D)  center of mass is at its middle. 
E)  center of mass projects onto the floor at a point outside the outline of its base. 
A)  height is greater than its width. 
B)  center of mass is below its middle. 
C)  center of mass is above its middle. 
D)  center of mass is at its middle. 
E)  center of mass projects onto the floor at a point outside the outline of its base.

Question 7

The form of Hooke's law relating shear stress to shear strain is
F/A = E $\Delta$s/h
The figure shows a block subjected to shear stress. Which number corresponds to the surface area A in the equation just given?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 8

A wire of circular cross section of diameter d and length L is stretched an amount $\Delta$L by a steady force F. An equal force would produce how much stretch in a similar wire of diameter 2d and length 2L?

Accepted Answer

A)  $\Delta$L/8 
B)  $\Delta$L/4 
C)  $\Delta$L/2 
D)  2$\Delta$L 
E)  4$\Delta$L 
A)  $\Delta$L/8 
B)  $\Delta$L/4 
C)  $\Delta$L/2 
D)  2$\Delta$L 
E)  4$\Delta$L

Question 9

The object shown in the diagram is a cube of uniform density resting on a rough surface. The applied force   is balanced by the frictional force   fr. When the block is on the verge of tipping, the point of application of the normal force acting on the cube will be

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 10

A box rests on a horizontal surface with one edge against a small ridge as shown. If the force    is 840 N and the bottom right edge of the box is just slightly off the ground, what is the weight of the box? (Hint: With the right edge slightly off the ground, the forces applied by the floor and the ridge must be at the bottom left corner of the box, and the angle can be taken to be negligibly small.)

Accepted Answer

A)  420 N 
B)  590 N 
C)  840 N 
D)  1.7 $\times$ 103 N 
E)  2.4 $\times$ 103 N 
A)  420 N 
B)  590 N 
C)  840 N 
D)  1.7 $\times$ 103 N 
E)  2.4 $\times$ 103 N

Question 11

A 6.0-kg ball is held in the hand with the lower arm making a 90-degree angle with the upper arm. The lower arm and hand have a combined mass of 2.5 kg and a center of mass 18 cm from the elbow joint. The ball is 40 cm from the elbow joint. If the biceps muscle is 12 cm from the center-of-mass point of the lower arm and hand, calculate the force that the biceps muscle must exert in order to keep the lower arm and hand horizontal.

Accepted Answer

A)  466 N 
B)  48.0 N 
C)  392 N 
D)  233 N 
E)  none of the above 
A)  466 N 
B)  48.0 N 
C)  392 N 
D)  233 N 
E)  none of the above

Question 12

Use the following to answer question :  
-The horizontal boom supporting the sign is of uniform construction and weighs 50 N. If the sign weighs 150 N, the force exerted by the hinge on the boom is

Accepted Answer

A)  ~350 N 
B)  ~304 N 
C)  ~25 N 
D)  ~550 N 
E)  None of these is correct. 
A)  ~350 N 
B)  ~304 N 
C)  ~25 N 
D)  ~550 N 
E)  None of these is correct.

Question 13

Use the figure to the right to answer the next problems.
A ball of mass m and radius r is placed next to a step of height ½ r.  
-What is the magnitude of the force the contact point c exerts on the ball when the applied force F just lifts the ball off the floor?

Accepted Answer

A)  mg 
B)  1.5 mg 
C)  1.73 mg 
D)  2 mg 
E)  2.14 mg 
A)  mg 
B)  1.5 mg 
C)  1.73 mg 
D)  2 mg 
E)  2.14 mg

Question 14

A flat object resting on a horizontal frictionless surface is acted on by forces of equal magnitude as shown. The center of gravity of the object is indicated in each case. The object is in translational equilibrium in figure(s)

Accepted Answer

A)  3 and 4 
B)  1 and 2 
C)  2 and 4 
D)  1 only 
E)  4 only 
A)  3 and 4 
B)  1 and 2 
C)  2 and 4 
D)  1 only 
E)  4 only

Question 15

The boom in the figure is uniform and weighs 2.20 kN. The magnitude of the tension in the guy wire is

Accepted Answer

A)  ~0.635 kN 
B)  ~1.83 kN 
C)  ~1.94 kN 
D)  ~1.47 kN 
E)  None of these is correct. 
A)  ~0.635 kN 
B)  ~1.83 kN 
C)  ~1.94 kN 
D)  ~1.47 kN 
E)  None of these is correct.

Question 16

A wire has a diameter of 0.75 mm. It is stretched 0.2% of its original length when a mass of 5 kg is hung from it. What is the Young's modulus of the wire?

Accepted Answer

A)  1.4 $\times$ 1010 N/m2  
B)  5.6 $\times$ 1010 N/m2  
C)  1.7 $\times$ 1011 N/m2  
D)  5.6 $\times$ 108 N/m2  
E)  1.4 $\times$ 108 N/m2  
A)  1.4 $\times$ 1010 N/m2  
B)  5.6 $\times$ 1010 N/m2  
C)  1.7 $\times$ 1011 N/m2  
D)  5.6 $\times$ 108 N/m2  
E)  1.4 $\times$ 108 N/m2

Question 17

The center of gravity and the center of mass coincide if

Accepted Answer

A)  the body is in rotational equilibrium. 
B)  the body is in translational equilibrium. 
C)  the acceleration due to gravity is constant over the body. 
D)  the body is in both translational and rotational equilibrium. 
E)  any forces accelerating the body are constant. 
A)  the body is in rotational equilibrium. 
B)  the body is in translational equilibrium. 
C)  the acceleration due to gravity is constant over the body. 
D)  the body is in both translational and rotational equilibrium. 
E)  any forces accelerating the body are constant.

Question 18

An 800-kg mass is hung from a 1.5-m copper wire with a cross-sectional area of 0.35 cm2. Young's modulus for copper is 1.1 $\times$ 1011 N/m2. How much does the wire stretch?

Accepted Answer

A)  2.56 mm 
B)  2.97 mm 
C)  3.14 mm 
D)  3.86 mm 
E)  4.13 mm 
A)  2.56 mm 
B)  2.97 mm 
C)  3.14 mm 
D)  3.86 mm 
E)  4.13 mm

Question 19

A wire 2.5-m long has a cross-sectional area of 2.5 mm2. It is hung vertically, and a 4.5-kg mass is hung from it. By how much does the wire stretch if Young's modulus for that material is 2.0 $\times$1011 N/m2?

Accepted Answer

A)  0.22 mm 
B)  2.2 mm 
C)  0.022 mm 
D)  0.72 mm 
E)  0.072 mm 
A)  0.22 mm 
B)  2.2 mm 
C)  0.022 mm 
D)  0.72 mm 
E)  0.072 mm

Question 20

The horizontal bar in the figure will remain horizontal if

Accepted Answer

A)  L1 = L2 and R1 = R2  
B)  L1 = L2 and M1 = M2  
C)  R1 = R2 and M1 = M2  
D)  L1M1 = L2M2  
E)  R1L1 = R2L2  
A)  L1 = L2 and R1 = R2  
B)  L1 = L2 and M1 = M2  
C)  R1 = R2 and M1 = M2  
D)  L1M1 = L2M2  
E)  R1L1 = R2L2

The force combination that forms a simple couple is

Which of the following could not have units of N/m²?

A 3-m long wire with a diameter of 1.5 mm has a Young's modulus of 9 $\times$ 10¹⁰N/m². What mass hung from the wire would extend it by 3 mm?

Four happy kids are lining up and jumping off a diving board one after another. The kids, each with a mass of 40 kg, are situated as in the above figure, and the uniform board has a total mass of 60 kg. Calculate the force on the support closest to the water.

A design project requires you to construct a crane to lift a maximum of 5000 kg and with a maximum upward acceleration of 2 m/s², and with a safety factor of 5. If the cable is 20m long, by how much does the cable stretch when the crane is operating at the design limits?

An upright refrigerator tips over if its

A wire of circular cross section of diameter d and length L is stretched an amount $\Delta$ L by a steady force F. An equal force would produce how much stretch in a similar wire of diameter 2d and length 2L?

The object shown in the diagram is a cube of uniform density resting on a rough surface. The applied force is balanced by the frictional force _fr. When the block is on the verge of tipping, the point of application of the normal force acting on the cube will be

Use the following to answer question : -The horizontal boom supporting the sign is of uniform construction and weighs 50 N. If the sign weighs 150 N, the force exerted by the hinge on the boom is

Use the figure to the right to answer the next problems. A ball of mass m and radius r is placed next to a step of height ½ r. -What is the magnitude of the force the contact point c exerts on the ball when the applied force F just lifts the ball off the floor?

A flat object resting on a horizontal frictionless surface is acted on by forces of equal magnitude as shown. The center of gravity of the object is indicated in each case. The object is in translational equilibrium in figure(s)

The boom in the figure is uniform and weighs 2.20 kN. The magnitude of the tension in the guy wire is

A wire has a diameter of 0.75 mm. It is stretched 0.2% of its original length when a mass of 5 kg is hung from it. What is the Young's modulus of the wire?

The center of gravity and the center of mass coincide if

An 800-kg mass is hung from a 1.5-m copper wire with a cross-sectional area of 0.35 cm². Young's modulus for copper is 1.1 $\times$ 10¹¹ N/m². How much does the wire stretch?

A wire 2.5-m long has a cross-sectional area of 2.5 mm². It is hung vertically, and a 4.5-kg mass is hung from it. By how much does the wire stretch if Young's modulus for that material is 2.0 $\times$ 10¹¹ N/m²?

The horizontal bar in the figure will remain horizontal if

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

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 12: Static Equilibrium and Elasticity

The force combination that forms a simple couple is

Which of the following could not have units of N/m2?

A 3-m long wire with a diameter of 1.5 mm has a Young's modulus of 9 ×\times× 1010 N/m2. What mass hung from the wire would extend it by 3 mm?

Four happy kids are lining up and jumping off a diving board one after another. The kids, each with a mass of 40 kg, are situated as in the above figure, and the uniform board has a total mass of 60 kg. Calculate the force on the support closest to the water.

A design project requires you to construct a crane to lift a maximum of 5000 kg and with a maximum upward acceleration of 2 m/s2, and with a safety factor of 5. If the cable is 20m long, by how much does the cable stretch when the crane is operating at the design limits?

An upright refrigerator tips over if its

The form of Hooke's law relating shear stress to shear strain is F/A = E Δ\DeltaΔ s/h The figure shows a block subjected to shear stress. Which number corresponds to the surface area A in the equation just given?

A wire of circular cross section of diameter d and length L is stretched an amount Δ\DeltaΔ L by a steady force F. An equal force would produce how much stretch in a similar wire of diameter 2d and length 2L?

The object shown in the diagram is a cube of uniform density resting on a rough surface. The applied force is balanced by the frictional force fr. When the block is on the verge of tipping, the point of application of the normal force acting on the cube will be

Use the following to answer question : -The horizontal boom supporting the sign is of uniform construction and weighs 50 N. If the sign weighs 150 N, the force exerted by the hinge on the boom is

Use the figure to the right to answer the next problems. A ball of mass m and radius r is placed next to a step of height ½ r. -What is the magnitude of the force the contact point c exerts on the ball when the applied force F just lifts the ball off the floor?

A flat object resting on a horizontal frictionless surface is acted on by forces of equal magnitude as shown. The center of gravity of the object is indicated in each case. The object is in translational equilibrium in figure(s)

The boom in the figure is uniform and weighs 2.20 kN. The magnitude of the tension in the guy wire is

A wire has a diameter of 0.75 mm. It is stretched 0.2% of its original length when a mass of 5 kg is hung from it. What is the Young's modulus of the wire?

The center of gravity and the center of mass coincide if

An 800-kg mass is hung from a 1.5-m copper wire with a cross-sectional area of 0.35 cm2. Young's modulus for copper is 1.1 ×\times× 1011 N/m2. How much does the wire stretch?

A wire 2.5-m long has a cross-sectional area of 2.5 mm2. It is hung vertically, and a 4.5-kg mass is hung from it. By how much does the wire stretch if Young's modulus for that material is 2.0 ×\times× 1011 N/m2?

The horizontal bar in the figure will remain horizontal if

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

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

Which of the following could not have units of N/m²?

A 3-m long wire with a diameter of 1.5 mm has a Young's modulus of 9 $\times$ 10¹⁰N/m². What mass hung from the wire would extend it by 3 mm?

A design project requires you to construct a crane to lift a maximum of 5000 kg and with a maximum upward acceleration of 2 m/s², and with a safety factor of 5. If the cable is 20m long, by how much does the cable stretch when the crane is operating at the design limits?

A wire of circular cross section of diameter d and length L is stretched an amount $\Delta$ L by a steady force F. An equal force would produce how much stretch in a similar wire of diameter 2d and length 2L?

The object shown in the diagram is a cube of uniform density resting on a rough surface. The applied force is balanced by the frictional force _fr. When the block is on the verge of tipping, the point of application of the normal force acting on the cube will be

An 800-kg mass is hung from a 1.5-m copper wire with a cross-sectional area of 0.35 cm². Young's modulus for copper is 1.1 $\times$ 10¹¹ N/m². How much does the wire stretch?

A wire 2.5-m long has a cross-sectional area of 2.5 mm². It is hung vertically, and a 4.5-kg mass is hung from it. By how much does the wire stretch if Young's modulus for that material is 2.0 $\times$ 10¹¹ N/m²?