Biomechanics Final Exam

Consider person A walking at a normal walking speed on a moving walkway. Which of the following statmenets is most accurate?

a. someone walking in the global reference system would be walking faster than person A

b. someone standing in the local reference system would be moving faster than person A

c. someone walking in the global reference system would consider person A to be walking fast

d. someone walking in the local reference system would consider person A to be walking slowly

someone walking in the global reference system woud consider person A to be walking fast

Which of the following represents the free body diagram in the image?

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5

If a volleyball player jumps from the ground to perform a spike with an initial angular momentum of 0, what would expect to see as the arm swings forward to strike the ball?

a. fast rotation of the legs in the opposite direction as the arms

b. slow rotation of the legs in the same direction as the arms

c. no motion of the body

d. fast rotation of the legs in the same direction as the arms

e. slow rotation of the legs in the opposite direction as the arms

slow rotation of the legs in the opposite direction as the arms

How are successful and skillful performances typically measured biomechanically in sport and activity?

A) displacement

B) velocity

C) acceleration

D) force

B & C

In a biomechanical model, the reference system used to define lift is typically placed with the origin where?

center of mass

In a biomechanica model, the reference system used to define contact force is typically placed with the origin where?

center of pressure

Which of the following muscles exerts no force at the joint?

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none of these

Based on the angle of pull, which muscle has the smallest stabilizing component in the image?

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teres major

All of the following are examples of decreasing friction to increase performance except which?

a. sharp ice skates

b. chalk on a gymnast hands

c. wax on skis

d. the sole of a bowlers shoe

all of these are examples of increasing friction to increase performance

If a ground reaction force is 500 N, what is the magnitude and direction of the acceleration of a 100 kg runner from the ground reaction force?

a magnitude of 5 m/s² in the opposite direction of the reaction force

When moving through the air as a projectile, how would your body move around your center of mass if you were to abduct both legs?

your body would move downward

In biomechanics, the magnitude of the contact force can be associated with which of the following

a. newtons 2nd law

b. newtons 3rd law

c. strength training

d. technique training

B & C

Whether surface drag or form drag is dominant component of overall drag depends primarily on which factor?

relative velocity

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Which of the following categories would biomechanical research on shoes most likely be included?

stress research

Which of the following research studies investigates kinematics?

a. effect of step width manipulation on tibial stress during running

b. a three dimensional, six segmental chain analysis of forceful overarm throwing

c. relationship between rotator cuff strength parameters and throwing velocity of college baseball players

d. comparison of ground reaction force asymmetry in one and two legged countermovement jumps

e. effect of the shoulder shoulder position on the bicep brachii EMG in a different dumbbell curls

f. dynamics of forward swinging skills on the parallel bars

B, C, and F

A lift force can be created by all of the following except which?

a. all of these will create a lift force

b. spinning a spherical object

c. the natural shape of an object

d. presenting the object with an angle of attack

e. creating a pressure gradient on the elading and trailing edges of the object

creating a pressure gradient on the lead and trailing edges of the object

If two football players collide in an impact, player #1 has twice the mass of player #2, what will happen to the velocity after the impact of player #2

increase 2x

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In which activity does drag force facillitate horizontal movement in a global reference system?

swimming

In a bounce pass, a basketball contacts the ground with initial velocity of 15 m/s at an angle of incidence of 60. What is the post impact velocity? What is the angle of rebound?

10 m/s

60 deg

A muscle is contracting with a dominant role as a stabilizer, and exerts a dislocating force at the joint. What is its angle of pull?

A)

135-degrees

B)

None of these.

C)

90-degrees

D)

110-degrees

E)

25-degrees

B) None of these.

Which of the forces below is affected by area of contact?

(A) weight

(B) friction

(C) buoyancy

(D) drag

(E) lift

D and E

In which activity does a lift force facilitate horizontal movement in a global reference system?

A) skydiving

In which activity does drag force facilitate horizontal movement in a global reference system?

swimming

When comparing performance of the same tennis player with different types of shoes and on different types of surfaces (e.g., hard-court, grass, and clay), which of the factors from the list to the right will affect friction between the player's shoe and the surface?

normal force

coefficient of friction

weight

area of contact

2 only

A lift force can be created by all of the following EXCEPT which?

a)

the natural shape of an object

b)

presenting the object with an angle of attack

c)

spinning a spherical object

d)

creating a pressure gradient on the sides of the object

e)

All of these will create a lift force.

e) All of these will create a lift force.

Assuming everything else is equal, under which of the following conditions will the drag force be the least?

The drag force is the same in each of these conditions.

Three vectors have the following polar coordinates: (5 N, 45°), (5 N, 90°), and (5 N, 225°). Which of the following graphs illustrates the resultant vector?

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Based on the angle of pull, which muscle has the greatest stabilizing component in the image? (NOTE: Use the tail of each black arrow for the insertion point.)

coracobrachialis