Question 1

When you squeeze a small stress-ball on all sides in your palm you decrease its volume to ¾ of its original volume. What is the volume strain on the ball?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 2

If you grab each end of a pencil and try to pull the ends apart, you are putting the pencil under tension or tensile stress; if you push the ends toward each other, you are putting the pencil under

Accepted Answer

A)  volume stress. 
B)  compressive stress. 
C)  shear stress. 
D)  Both A and B are correct. 
E)  Only C is correct.

Question 3

The table below shows ultimate tensile strengths ) and Young's moduli ) for tungsten W) and silicon Si). Based on the information in the table, what is the ratio of ultimate tensile strains for these materials, namely .

Accepted Answer

A)  0.0980 
B)  10.2 
C)  0.0459 
D)  2.77 
E)  0.457

Question 4

A college student measures his height just before he goes to bed at night and also right after he gets up in the morning the next day. His measurements are 1.80 m, and 1.82 m, respectively. What is the compressive strain on his body due to the normal force and the gravity that are acting on him all day long?

Accepted Answer

A)  2/182 
B)  2/180 
C)  1.82 m-1.80 m 
D)  182/180 
E)  180/182

Question 5

All elastic materials obey Hooke's law in the region of small strain.

Accepted Answer

A)  True 
B)  False

Question 6

Fill in the blank. If you double the cross-sectional area of a steel rod, you would __________ the Young's modulus of steel.

Accepted Answer

A)  double 
B)  triple 
C)  quadruple 
D)  cut in half 
E)  not change

Question 7

True or false? Volume stress is equal to the pressure on the object.

Accepted Answer

A) True 
 B)False

Question 8

Use the following figure to answer the following question:  
-A steel wire and an aluminum wire of the same length L and diameter d are joined to form a wire of length 2L. The wire is fastened to the ceiling and a mass m is attached to the other end. If the masses of the wires are negligible relative to mass m, the ratio of the strain in the aluminum wire to the strain s in the steel wire is

Accepted Answer

A)  less than 1. 
B)  equal to 1. 
C)  greater than 1. 
D)  dependent on mass m. 
E)  impossible to determine.

Question 9

Fill In the blank. If you double the radius of a steel cable without changing its length, you would __________ its elastic constant.

Accepted Answer

A)  double 
B)  triple 
C)  quadruple 
D)  halve 
E)  not change

Question 10

Young's modulus depends on the geometric shape of the object:

Accepted Answer

A) True 
 B)False

Question 11

The point that identifies the fracture point of the material whose graph of stress as a function of strain is shown is

Accepted Answer

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

Question 12

A wire has a diameter of 0.75 mm. It is stretched 0.20% of its original length when a mass of 5.0 kg is hanging from it. What is the Young's modulus of the wire?

Accepted Answer

A)  1.4  x 1010 N/m2 
B)  5.6  x 1010 N/m2 
C)  1.7  x 1011 N/m2 
D)  5.6  x 108 N/m2 
E)  1.4  x 108 N/m2

Question 13

If you measure the magnitude of the force required to stretch a typical laboratory spring as a function of the MAGNITUDE of stretch, which of the graphs shown would best represent your data?

Accepted Answer

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

Question 14

A spring is made of a wire of radius r and length L. If the radius of the wire and the length of the wire were doubled, the spring constant of the spring would

Accepted Answer

A)  double. 
B)  quadruple. 
C)  halve. 
D)  quarter. 
E)  remain unchanged.

Question 15

The graph shows force exerted by two springs with spring constants and , respectively, as a function of extension/compression. Which of the following statements is not true?

Accepted Answer

A)  At the same extension force exerted by spring one is larger than force exerted by spring two 
B)  When the force exerted by spring one is the same as force exerted by spring two, the latter is extended more. 
C)  If both springs have the same dimensions, spring one is made from a stiffer material than spring two. 
D)  If the springs are made of the same material and have the same length, spring one has a smaller cross-sectional area than spring two. 
E)  If the springs are made of the same material and have the same cross-sectional areas, spring one is shorter than spring two.

Question 16

The bulk modulus of mercury is If a drop of benzene with a volume is moved from a vacuum chamber to a high-pressure chamber with , the volume of the droplet

Accepted Answer

A)  increases by 1.14× 10-4  mm3 . 
B)  increases by 1.14× 10-7  mm3 . 
C)  doesn't change. 
D)  decreases by 1.14× 10-4  mm3 . 
E)  decreases by 1.14× 10-7  mm3 .

Question 17

A cable lifting a 4.00-lb bowling ball stretches by 3.00 mm. If the cable is cut in half and both halves are used together to lift the same bowling ball, each cable will stretch by

Accepted Answer

A)  0.50 mm. 
B)  0.75 mm. 
C)  1.00 mm. 
D)  1.25 mm 
E)  1.50 mm.

Question 18

A 1.83 m-long aluminum "singing" rod is vertically balanced on the floor on one of its ends. Calculate the pressure on the ground exerted by the road due to the weight of the road. The density of Al is QUOTE 2.70×103 kg/m3 and the diameter of the rod is 1.27 cm.

Accepted Answer

A)  2.7 N/m2 
B)  8.4 N/m2 
C)  2.7×104 N/m2 
D)  4.8×104 N/m2 
E)  4.94×103 N/m2

Question 19

An 800-kg mass is hung from a 1.50-m copper wire with a cross-sectional area of 0.350 cm2. Young's modulus for copper is 1.10  x 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

Question 20

A cube expands by 6.94 mm3 when moved from normal conditions to a vacuum chamber. If the bulk modulus of the material is 28.5 GPa, what is the length of the side of that cube?

Accepted Answer

A)  1.95 mm 
B)  0.125 m 
C)  4.42 cm 
D)  12.5 m 
E)  1.95 km

Exam 9: Elastic Properties of Matter: Stress and Strain