PPT Statics
Name Date Period
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 v = d/t, solve for t. t =
2) 8/R = 4/T. Solve for T. T =
3) Define center of mass.
4) When is an object balanced?
5) There is a 4-gram mass on the left side of a balance 20 centimeters from the center. There is a 5-gram mass on the right side of the balance. How far from center is the mass on the right to keep the system balanced?
6) There is a 4-gram mass on the left side of a balance,10 centimeters from the center. There is a 5 gram mass also on the left side of the balance, 20 centimeters from the center. How far must a 20-gram mass be from center on the right side to keep the system balanced?
7) Name three roles that bones play in physiology.
8) What are the four types of bones?
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9) What is the technical term for a push or a pull?
10) Which type of stress is represented in this drawing?
11) Name three ways to make a material stronger.
12) Label the parts on this cross section of a bone:
bone matrix
marrow membranous sheath
13) What is a compound fracture?
14) What do ligaments do?
15) What type of joint is your hip?
16) In a second class lever the ______is in the middle.
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17) You want to lift a large boulder that weighs 1000 kg. You have a 3 meter bar to use as a class 1 lever. If you set up the bar so that the boulder is 0.2 meters from the fulcrum, and you weigh 100 kg, what is the minimum distance you can be from the fulcrum on the other side to move the boulder? Ignore the weight of the bar.
18) What class of lever is your elbow when you straighten your arm?
19) Why is a small animal less likely to be injured in a long fall than a large animal?
20) In physiology, what does "form follows function" mean?
21) What does this graph tell you about the relationship between force and distance? Distance
Force
22) A human femur can withstand about 55 kg/cm2 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 cm2. A typical human weighs about 70 kg, so the ratio of mass to cross-sectional area is 70 kg/3 cm2 (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.
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# Pts Answer Steps Concept Name date period 1 2 t = d/v 1 3 variables 2 2 T = R/2 1 proportions or 4 variables 3 2 The point where the ∑md in all center of mass directions is equal. An object acts as if all its mass is at the center of mass. 4 2 When its center of mass is above (or center of mass, base of below) its base of support support 5 2 16 cm 1 center of mass 6 2 7 cm 2? center of mass 7 2 protection, support, movement, mineral bone function storage, red blood cell manufacturing 8 2 long, short, flat, irregular bone types 9 2 force force 10 2 tension stresses 11 2 combine it with other materials, put a strength of materials bend in it, make it thicker, shape it into a tube, put it on edge, 12 2 marrow, matrix, periosteum bone structure 13 2 when the bone is broken and sticks bone fractures through the skin 14 2 connect bones to bones joint structure 15 2 ball and socket joint types 16 2 resistance lever types 17 2 2 m 2 leverage 18 2 first class physiological levers 19 2 because its surface to volume ratio is scaling – area to weight larger, so it falls slower due to air resistance 20 2 the shape of something is determined by form follows function what it does 21 2 as distance increases, force decreases, graphs, Fd = k or vice versa 22 2 No, the femur would break. 2-3? scaling – area to weight 3370 kg /323 cm2 = 70 kg/cm2, which is more than 55 kg/cm2. EC Total 44
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