exam 1, 2

Question 1

a free body diagram displays
a. the weight distribution of a body on a surface
b. the pressure distribution of a body on a surface
c. the mass distribution of a body
d. the forces acting on a body
e. none of the above

Answer 1

d

Question 2

If two forces lying in the same plane are added together and the result is zero, which of the following is true of the forces?
a. They are opposite in direction.
b. They are equal in magnitude.
c. Both a and b are true.
d. none of the above

Answer 2

c

Question 3

The force that acts parallel to an object in contact with a surface is called
a. friction force
b. normal contact force
c. internal force
d. colinear force
e. resolved force

Answer 3

a

Question 4

A force can be
a. a push
b. a pull
c. either a or b
d. simultaneously a push and a pull
e. none of the above

Answer 4

c

Question 5

A 90 kg weightlifter exerts a 1000 N force upward against a 50 kg barbell. How large is the net vertical force acting on the barbell?
a. 1050 N
b. 510 N
c. 1050 kg
d. 950 kg
e. 1490 N

Answer 5

b

Question 6

Two teams are competing in a tug-of-war. George (170 lb), Laura (120 lb), and Jenna (110 lb) are on team A. The coefficient of static friction between their shoes and the floor is 0.40. Bill (230 lb), Hilary (140 lb), and Chelsea (130 lb) are on team B. The coefficient of static friction between their shoes and the floor is 0.30. Which team will be able to create more static friction force and thus be more likely to win the tug-of-war?

Answer 6

George’s team, static coefficient is greater, harder for them to move

Question 7

to fully define a vector quantity, you must specify
a. length and magnitude
b. length and area
c. area and direction
d. direction and magnitude
e. none of the above

Answer 7

d

Question 8

which of the following statements is true of the amount of horizontal force required to start in motion an object sitting on a horizontal surface
a. it must be greater than the coefficient of kinetic friction
b. it must be greater than the coefficient of static friction
c. it must be greater than the max kinetic friction force
d. it must be greater than the max static friction force
e. none of the above

Answer 8

d

Question 9

which of the following, when present, is NOT an external force applied to a runner
a. gravitational force
b. weight
c. friction
d. muscle force
e. all of the above

Answer 9

c

Question 10

Used to describe a force that __________ movement, traction is sometimes used in place of the term __________.
a. initiates; contact force
b. initiates; friction
c. initiates; muscle force
d. hinders; friction
e. hinders; contact force

Answer 10

b

Question 11

Velocity is calculated as
a. distance divided by time
b. displacement divided by time
c. force divided by time
d. force times distance
e. force divided by distance

Answer 11

b

Question 12

If an object’s initial coordinates are (3, 5, 0), and the final coordinates are (6, -2, -4), what is the object’s displacement?
a. 3 units right, 3 units down, and 4 units forward
b. 3 units left, 7 units up, and 4 units forward
c. 9 units right, 7 units down, and 4 units backward
d. 3 units right, 7 units down, and 4 units backward
e. need more information to calculate

Answer 12

d

Question 13

At 3 s into a run, a football player is traveling at +3 m/s. Four seconds later, the player is traveling at -5 m/s. vi is equal to
a. 0 m/s
b. 3 m/s
c. 5 m/s
d. -3 m/s
e. -5 m/s

Answer 13

b

Question 14

Units of acceleration are
a. s
b. m
c. m/s
d. m/s2
e. mi/h

Answer 14

d

Question 15

Which of the following terms best describes linear motion along a curved line?
a. rectilinear
b. curvilinear
c. rotational
d. general
e. none of the above

Answer 15

b

Question 16

When a runner has completed one full lap around a 400 m track, what is the runner’s displacement with respect to the starting position?
a. 400 m
b. 400 m multiplied by 2
c. zero
d. need more information to calculate

Answer 16

c

Question 17

Which of the following is not a vector quantity?
a. distance
b. speed
c. neither a nor b
d. both a and b

Answer 17

d

Question 18

What is the average speed of a cyclist who covers -15 mi in 30 min?
a. 5 mi/h
b. 10 mi/h
c. 30 mi/h
d. 60 mi/h
e. need more information to calculate

Answer 18

c

Question 19

A swimmer is traveling with an average velocity of -3.2 m/s. How far does the swimmer travel in 3 s?
a. 1.1 m
b. 6.9 m
c. 9.6 m
d. A swimmer cannot travel in the negative direction.
e. need more information to calculate.

Answer 19

c

Question 20

The horizontal velocity of Serena’s tennis serve is measured as 112 mi/h (50 m/s). Horizontally, the ball travels 82 ft (25 m) before reaching Venus (Serena’s opponent). If the ball didn’t slow down when it bounced or because of air resistance, how long would it take to reach Venus?
a. 0.25 s
b. 0.75 s
c. 0.50 s
d. 1.0 s
e. 2.0 s

Answer 20

c

Question 21

Newton’s first law focuses on
a. action-reaction
b. acceleration
c. inertia
d. gravity
e. none of the above

Answer 21

c

Question 22

Which of Newton’s laws is described by the equation F = ma?
a. first
b. second
c. third
d. fourth
e. law of gravitation

Answer 22

b

Question 23

as the mass of an object increases, what happens to its inertia?
a. decrease
b. increase
c. stays the same
d. weighs more
e. mass and inertia are not related

Answer 23

b

Question 24

if a body of constant mass is traveling with a constant velocity,
a. there must be no force acting on the body
b. there must be no net force acting on the body
c. there must be a force acting on the body
d. there must be a net force acting on the body
e. need more info

Answer 24

b

Question 25

if a bag has a mass of 25kg, how much force must you apply vertically to lift it off of a baggage cart a. less than 250N b. 250N c. greater than 250N d. need more info

Answer 25

c

Question 26

according to newtons third law, when two bodies collide, a. the effects of the force applied to each body will be exactly the same b. the effects of the force applied to each body will be exactly the same if the mass of each body is approx the same c. the force applied to each body will be the same size d. the force applied to each body will be the same size if the mass of each object is approx the same

Answer 26

c

Question 27

a 500 N gymnast performs a stationary handstand on the high bar. how much force is exerted by the bar on the gymnasts hands a. 50N b. 100N c. 500N d. 2500N e. need more info

Answer 27

c

Question 28

the product of a force and the time during which the force acts on a body defines a. linear momentum b. linear velocity c. linear acceleration d. linear impulse e. linear displacement

Answer 28

d

Question 29

if you increase the time during which a constant force is applied to an object, what effect foes this have on the impulse given to the object a. increases impulse b. decreases impulse c. doesn't affect impulse d. causes impulse to equal zero e. none of the above

Answer 29

a

Question 30

power is equal to a. the act of force a muscle can generate b. force times distance c. work d. force times displacement divided by time e. none of the above

Answer 30

d

Question 31

mechanical work is performed in all of these types of muscle activity (contraction) except for a. isometric b. concentric c. eccentric d. mechanical work is performed in all of the above e. mechanical work is not performed in any of the above

Answer 31

a

Question 32

when catching a baseball or softball with a glove a. the ball performs positive work on the glove, and the glove performs negative work on the ball b. the ball performs negative work on the glove and the glove performs positive work on the ball c. positive work is performed on both the ball and glove d. negative work is performed on both the ball and glove e. no work is performed since the work on the ball and the work on the glove cancel each other out

Answer 32

a

Question 33

a person performs a bench press. the bars mass is 50kg. when this persons arms are extended the bar is .6m above the starting point. how much work did the person do to push the bar off his chest to full extension of his arms a. 0Nm b. 200Nm c. -300Nm d. 600Nm e. -600Nm

Answer 33

b

Question 34

kinetic energy is the energy a. due to deformation b. due to motion c. due to position d. due to weight e. kids use to run around a room

Answer 34

b

Question 35

gravitational potential energy is the energy a. due to deformation b. due to motion relative to the earth c. due to the position relative to the earth d. due to weight e. kids use to run around a room

Answer 35

c

Question 36

during the pitching motion, a baseball pitcher exerted an avg horizontal force of 80N against the .15kg baseball while moving it through a horizontal displacement of 2.0m before release. the amount of work performed by the pitcher on the baseball was a. 40J b. 80J c. 82J d. 160J e. 320J

Answer 36

d

Question 37

if a 25 kg child climbs two steps of 20cm each, the work performed is a. 10Nm b. 100Nm c. 1000Nm d. 10,000Nm e. need more info

Answer 37

b

Question 38

the capacity for doing work that a body possesses because of its position or configuration is known as a. potential energy b. kinetic energy c. moment of inertia d. power e. torque

Answer 38

a

Question 39

the soft foam pit is used for landing during the pole vault. the foam pit cushions the landing of the vaulter by a. reducing the friction encountered b. reducing the displacement during the landing c. increasing the friction encountered d. increasing the displacement during the landing e. none of the above

Answer 39

d

Question 40

if an athlete moves faster, what happens to her momentum a. increase b. decrease c. velocity has no impact on momentum d. momentum equals 0 e. converts to impulse

Answer 40

a

Question 41

the moment arm is defined as a. the distance from the POA of a force to a specified axis of rotation b. the distance from the line of action of a force to a specified axis of rotation c. the perpendicular distance from the line of action of a force to a specified axis of rotation d. all of the above e. none of the above

Answer 41

c

Question 42

torque is defined as a. the tendency of a force to cause rotation b. the turning effect of a force c. the product of force and moment arm d. all of the above e. none of the above

Answer 42

d

Question 43

two forces acting on an object to cause only rotation of the object create a. force couple b. negative forces c. negative torques d. positive torques e. none of the above

Answer 43

a

Question 44

what is the torque if a 50N force is applied 2m from the axis of rotation a. 200Nm b. 100Nm c. 50Nm d. 25Nm e. 10Nm

Answer 44

b

Question 45

as a joint is moved through its range of motion when strength training with free weights, such as doing the arm curl, the moment arm for the muscle crossing the joint will get a. longer b. shorter c. either a or b d. none of the above

Answer 45

c

Question 46

if the moment arm is 5cm, and the force is 100N, the magnitude of the torque will be a. 5Nm b. 50Nm c. 500Nm d. 5000Nm e. need more info

Answer 46

a

Question 47

for any given muscle, the moment arm is largest when the angle of muscle pull on the bone is closest to a. 0 degrees b. 45 c. 90 d. 180 e. depends on the segment

Answer 47

c

Question 48

in the average female, the COG is located a. higher than the avg male b. near the sternum c. in the same place as the avg male d. lower than the avg male

Answer 48

d

Question 49

stability may be increased by a. raising center of mass b. decreasing number of contact points in the base of support c. widening the base of support perpendicular to any oncoming force d. leaning away from an oncoming force e. none of the above

Answer 49

e

Question 50

what happens to your COG when you add a 200 N suitcase to your hand held out to your side a. shift in direction of suitcase b. shifts in the direction opposite of suitcase c. does not move d. moves outside your body e. need more info

Answer 50

a

Question 51

which of the following is not a unit of angular displacement a. radian b. revolution c. degree d. watt e. all of the above are units

Answer 51

d

Question 52

an angle formed between two body segments is an example of a. absolute angle b. relative angle c. double jointed angle d. goniometric angle e. radial angle

Answer 52

b

Question 53

the anglar distance covered by a rotating object will always be a. greater than the angular displacement by the object b. smaller than the angular displacement covered by the object c. at least equal to, if not greater than, the angular displacement covered by the object d. at least equal to, if not smaller than, the angular displacement covered by the object e. the angular distance depends on the radius

Answer 53

c

Question 54

for a rotating object, the acceleration directed toward the center of rotation is called a. tangential acceleration b. rotary acceleration c. centrifugal acceleration d. linear acceleration e. centripetal acceleration

Answer 54

e

Question 55

which plane is perpendicular to the longitudinal axis a. frontal b. sagittal c. transverse d. oblique e. vertical

Answer 55

c

Question 56

a person riding a bicycle forward in a straight line would be moving in the a. transverse plane b. sagittal plane c. frontal plane d. AP plane e. diagonal plane

Answer 56

b

Question 57

when cycling forward in a straight line, the knee is rotating about a(n) ____ axis a. longitudinal b. vertical c. anteroposterior d. transverse e. vertical

Answer 57

d

Question 58

which of the following motions occurs primarily in the sagittal plane a. running b. a cartwheel c. pirouette d. all of the above e. none of the above

Answer 58

a

Question 59

which of the following motions occurs primarily in the transverse (horizontal) plane a. running b. a cartwheel c. pirouette d. all of the above e. none of the above

Answer 59

c

Question 60

in anatomical terminology, the front portion of the body is called a. superior b. inferior c. anterior d. posterior e. none of the above

Answer 60

c

Question 61

an example of a rotation about the longitudinal axis is a a. front walk over b. twist c. somersault d. cartwheel e. jumping jack

Answer 61

b

Question 62

by convention, positive angular direction is a. clockwise b. counterclockwose c. always in the direction of flexion d. always in the direction of extension e. semicircular

Answer 62

b

Question 63

a gymnast dismounts the uneven parallel bars with some angular momentum about her transverse axis. just after release, she is in a piked position. she then extends into a layout position before she lands. what happens as a result of this action a. her moment of inertia increases and she rotates slower b. her angular momentum decreases c. her angular momentum increases d. her moment of inertia decreases as she rotates faster e. none of the above

Answer 63

a

Question 64

when knee flexion is increased during running, the moment of inertia of the lower extremity about the hip is a. increased b. decreased c. remains the same d. depends on the anthropometric characteristics of the leg e. moment of inertia cannot be measured about the hip

Answer 64

b

Question 65

angular impulse is the product of a. force and the time that force is applied b. torque and the time that torque is applied c. angular inertia and angular momentum d. mass and angular velocity e. force and torque

Answer 65

b

Question 66

as an objects mass increases, what happens to its moment of inertia a. increase b. decrease c. mass has no influence on moment of inertia d. it changes the location of mass e. this depends on how the added mass is distributed

Answer 66

e

Question 67

in the equation for moment of inertia, which variable is most influential a. mass b. impulse c. radius of gyration d. center of gravity e. all are equally influential

Answer 67

c

Question 68

the SI unit for torque are a. ft*lb b. N c. Nm d. PSI e. none of the above

Answer 68

c

Question 69

what is the relationship between torque and angular acceleration a. the greater the torque acting on the axis of rotation, the greater the angular acceleration of a given body b. the greater the torque acting at the axis of rotation, the lower the angular acceleration of a give body c. the lower the torque acting at the axis of rotation, the greater the angular acceleration of a given body d. torque and angular acceleration are not related

Answer 69

a

Question 70

when a body is completely motionless, it is considered to be a. in dynamic equilibrium b. in static equilibrium c. undergoing positive acceleration d. undergoing negative acceleration e. a body is never motionless

Answer 70

b

Question 71

the statement "a rotating body will maintain a state of constant angular motion unless acted on by an external torque" refers to a. newtons 1st law b. newtons 2nd law c. newtons 3rd law d. newtons 4th law e. newtons torque law

Answer 71

a

Question 72

a diver attempt a 1.5 front flip in a tuck position off the 1m board but only rotates 1.25 times. which of the following suggestions is not appropriate for the diver a. jump higher b. tuck looser c. tuck sooner d. release tuck later e. generate more angular momentum going into the dive

Answer 72

b

Question 73

You are coaching a Little League baseball team. One of your players is having a hard time hitting the ball. He does a good job of choosing which pitches to swing at, but he keeps missing because his bat doesn't get around fast enough. What would you suggest that he do (give one suggestion)? Explain the reason for your suggestion.

Answer 73

choke up on the bat or choose a lighter, shorter bat. both of these suggestions reduce the moment of inertia of the bat about the swing axis

Question 74

a ____ angular velocity of a football, flying disc, or discus contributes to a ____ flight of the implement a. faster, less stable b. slower, less stable c. faster, more stable d. slower, more stable e. b and c

Answer 74

e

Question 75

the principle or law used to describe lift is called a. archimedes principle b. Bernoullis principle c. Wolffs law d. pascals law e. newtons principle

Answer 75

b

Question 76

the vertical force that always acts upward is a. gravity b. acceleration c. drag force d. turbulance e. buoyant force

Answer 76

e

Question 77

which shape is most conductive to optimizing lift a. sphere b. foil c. oblong d. rectangle e. square

Answer 77

b

Question 78

which form of drag would have the greatest effect on a swimmer performing the crawl (freestyle) stroke in a smooth ocean a. force drag b. form drag c. wave drag d. pressure drag e. shark drag

Answer 78

b

Question 79

for a submerged object, the buoyant force acts as the a. COG b. center of mass c. radius of rotation d. center of volume e. all of the above

Answer 79

d

Question 80

the concept that explains how a spinning baseball changes direction is called a. Pedros theory b. the Bourne identity c. angular impulse d. radius of gyration e. Magnus effect

Answer 80

e

Question 81

In which conditions would the effects of air resistance be more significant: in a high-altitude venue on a hot day, or in a low-altitude venue on a cool day?

Answer 81

low altitude, cool day

Question 82

water pressure ___ with depth. pressure is defined as ____ a. increases linearly, force per unit area b. decreases linearly, force per unit area c. increases vertically, buoyant force d. decreases vertically, buoyant force e. increases linearly, the weight go the fluid displaced by the object

Answer 82

a

Question 83

when we consider the dynamic fluid forces acting on an object, we must take into account the velocity of the object as well as the velocity of the fluid itself true or false

Answer 83

true

Question 84

the size of the surface drag is affected by a. the coefficient of drag b. density of the fluid c. cross sectional area of the object d. square of the relative velocity e. all of the above

Answer 84

e

Question 85

a lift force can be directed upward, downward or in any direction that is perpendicular to the fluid flow true or false

Answer 85

true

Question 86

the wind blowing in the face of a 55kg distance runner will have the same effect as the same wind blowing in the face of a 75kg distance runner true or false

Answer 86

false

Question 87

when applying rigid-body mechanics to the study of human beings, which assumption is made a. the body does not deform by bending, stretching or compressing b. the segments are fixable links c. the joints provide friction during movement d. the body deforms by bending, stretching or compressing e. all of the above are assumed

Answer 87

a

Question 88

when a stretched material does not return to its original shape, it is called a. elastic b. plastic c. refractive d. porous e. stiff

Answer 88

b

Question 89

which force exerts a pull on the body acted upon a. shear b. compression c. tension d. torsion e. all of the above

Answer 89

c

Question 90

which force exerts a squeezing effect on the body acted upon a. shear b. compression c. tension d. torsion e. all of the above

Answer 90

b

Question 91

a load that produces twisting of a body around its longitudinal axis is called a a. shear load b. tensile load c. compressive load d. torsion load e. combined load

Answer 91

d

Question 92

identify the true statement a. increasing the surface area over which a force is distributed decreases the act of stress acting on the surface b. decreasing the surface area over which a force is distributes decreases the act of stress acting on the surface c. both a and b d. neither a or b

Answer 92

a

Question 93

how many square cm are in a square m a. 100 b. 1000 c. 10000 d. 100000 e. 1000000

Answer 93

c

Question 94

at 0 degree knee flexion, the contact area between the tibia and the femur is 1.6cm^2. if the compressive force across the tibiofemoral joint is 1350N, the mechanical stress (in MPa) would be calculated to be a. 8.44 b. 84.37 c. 843.75 d. 8437.5 e. need more info

Answer 94

a

Question 95

stress is defined as the a. mass per unit volume b. force per unit volume c. force per unit area d. displacement per unit time e. force per unit mass

Answer 95

c

Question 96

connective tissues such as tendon and ligament are ____, meaning that they do not have the same mechanical properties in every direction a. ductile b. crimped c. isotropic d. anisotropic

Answer 96

d

Question 97

what component of bone is primarily responsible for its compressive strength a. collagen b. minerals c. water d. vitamins e. marrow

Answer 97

b

Question 98

bone is strongest in resisting a. tensile stress b. shear stress c. compressive stress d. bone is equally strong in resisting all types of stress

Answer 98

c

Question 99

when articular cartilage is exposed to constant compressive stress, the strain in the cartilage will increase radially with time. this pattern is called a. elasticity b. creep c. collagen d. stress-strain curve

Answer 99

b

Question 100

ligaments are less stiff and slightly weaker than tendons because a. ligaments have more elastin and less aligned collagen fibers b. ligaments have less elastin and more aligned collagen fibers c. ligaments have a diff type of collagen fiber d. ligaments have randomly arranged collagen fibers

Answer 100

a