PPT Statics
Name
Period
Date
For each problem,
 choose the best answer and,
 on multiple choice questions, mark the Scantron sheet (match the question number) or
 fill in the blank(s) or
 follow the instructions for that problem.
 Don’t forget the units in your answers! Show your work for partial credit.
1) If p = F/A, solve for A. A =
2) Q/R = S/T. Solve for T. T =
3) What is the definition of center of mass? a) The point of an object around which its weight is evenly balanced. b) The point of an object where gravity is pulling the hardest. c) The average mass of an irregular shaped object. d) All of the above. e) None of the above.
4) An object that is balanced a) has a center of mass directly below the suspension point. b) has a center of mass directly above the base of support. c) can be described by the equation ∑F
 d = ∑F
 d. d) All of the above. e) None of the above.
5) If there is a 3-gram mass on the left side of a balance 15 centimeters from the center, and a 5-gram mass on the right side of the balance, how far from center is the mass on the right? a) 3 centimeters b) 9 centimeters c) 13 centimeters d) 15 centimeters e) 30 centimeters
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6) If there is a 2-gram mass on the left side of a balance that is 5 centimeters from the center, and a 4 gram mass also on the left side of a balance that is 10 centimeters from the center, how far must a 10 gram mass be from center on the right side to keep the system balanced? a) 5 centimeters b) 6 centimeters c) 8 centimeters d) 15 centimeters e) 80 centimeters
7) Which of these is NOT a role that bones play in physiology? a) Provide attachment sites for muscles. b) Produce red blood cells. c) Protect delicate organs. d) Store minerals. e) Absorb toxins.
8) What are the four types of bones? a) Long, flat, round, and smooth. b) Femur, rib, pelvis, and skull. c) Smooth, skeletal, striated, and cardiac. d) Long, short, flat, and irregular. e) Irregular, smooth, short, and flat.
9) The technical term for a push or a pull is a) Acceleration b) Stress c) Force d) Weight e) Momentum
10) Which type of stress is represented by this drawing? a) Tension b) Compression c) Torsion d) Shear e) Force
11) Which of the following would NOT make the material stronger? a) Combine flexible gauze with hard, brittle plaster. b) Place pieces of ribbed cardboard at right angles to one another. c) Roll a flat piece of plastic into a tube. d) Shift from a triangular frame to a square frame. e) Add a right angle bend to a flat piece of metal
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12) Label the parts on this cross section of a bone: bone matrix marrow membranous sheath
13) If someone twists your arm behind your back so that it is subject to a great deal of torsion, which fracture will most likely be the result? a) Greenstick b) Compound c) Ulnar d) Stress e) Spiral
14) What do ligaments do? a) Relieve friction between joints. b) Connect muscles to bones. c) Connect bones to bones. d) Contract and pull on bones, allowing them to move. e) Connect muscles to muscles.
15) Which of the following are correctly matched? a) Ball & socket joint – knee b) Hinge joint – wrist c) Gliding joint – shoulder d) Pivot joint – waist e) Hinge joint – ankle
16) In a third class lever the _________ is in the middle. a) bar b) effort c) fulcrum d) pivot e) resistance
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17) You want to lift a large boulder that weighs 200 kg. You have a 2 meter bar you can use as a class 1 lever. If you set up the bar so that the boulder is .5 meters from the fulcrum, and you weigh 80 kg, what is the minimum distance you can be from the fulcrum on the other side to lift the boulder? Ignore the weight of the bar. a) .5 meters b) .75 meters c) 1.25 meters d) 1.5 meters e) 1.75 meters
18) Which of these is an example of a third class lever in the body? a) Doing bicep curls. b) Nodding your head. c) Your femur. d) Doing push-ups. e) Standing on tip-toe.
19) If you and the evil monkey are fighting at the edge of a 5 meter cliff, why would he be more likely risk to knocking you off when it means he’ll go over the edge, too? a) He is just that evil. b) He is smaller than you, and is not as likely to get hurt falling from that height, since his surface area to volume ratio means he’ll fall slower due to air resistance. c) Monkeys are bouncier. d) He weighs less, so he won’t accelerate as quickly due to gravity. e) Monkeys are stronger than humans for their weight.
20) In physiology, the concept that form follows function means: a) The way something looks reflects what it does in the body. b) Things look the way they do so that we think they look nice. c) It is hard to figure out what something does unless we know what it looks like. d) The center of mass must be over the base of support. e) Function is not as important as form.
21) What does this graph tell you about the relationship between force and distance? a) Distance/force = a constant. b) Distance = force
2
. c) Force and distance increase at the same rate. d) As force increases, distance increases. e) As force increases, distance decreases.
Distance
Force
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22) A human femur can withstand about 55 kg/cm
2
before it breaks. A typical human femur is about 2 cm in diameter (1 cm in radius), so the cross-sectional area is about 3 cm 2 . A typical human weighs about 70 kg, so the ratio of mass to cross-sectional area is 70 kg/3 cm
2
(standing on one leg). If a giant human was 3 times as big in all three dimensions
(height, width, thickness), would one of their femurs be strong enough to hold their weight? What would the ratio of mass to cross-sectional area be? Show your work.
Extra Credit
You may have learned something in this section that isn’t on the test. Explain it. Use words, pictures, diagrams, graphs, etc. to demonstrate your knowledge.
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1.
2.
# Pts
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21. b a e d c b d
A = F/p
T = S

R/Q a d
Answer b c a b a e marrow, matrix, periosteum e c d
22. 2
23.
24.
25.
26.
EC
Total 44
No, the femur would break.
3
3 
70 kg /3
2 
3 cm
2
= 70 kg/cm
2
, which is more than 55 kg/cm 2 .
Steps
1 3 variables
Concept
1 proportions or 4 variables center of mass center of mass, base of support
1 center of mass
2? center of mass bone function bone types force stresses strength of materials bone structure bone fractures joint structure joint types lever types
2 leverage physiological levers scaling – area to weight form follows function graphs, F
 d = k
2-3? scaling – area to weight
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