Name Riley Morgan UIN# 726008903

KINE 426 – Exercise Biomechanics Midterm Exam

Law of cosines: c2 = a2 + b2 - 2•a•b•cosµ

Law of sines: a/sina = b/sinß = c/sin£
Fluid, air drag: FD = 1/2CD•Ar•r•v2

1. Hip flexion occurs in which anatomical plane?

a. coronal b. sagittal
c. transverse d. horizontal

2. During the football throw seen in Fig 1, what form of motion did the arm travel?
a. Rectilinear
b. Curvilinear
c. Rotational
Fig 1
3. Which of the following relationships is correct?
a. m = F/a
b. F = m/a
c. a = m/F
d. None of these answers are correct.

4. In Figure 1, if the arm starts the pass at 160 degrees relative to the origin and travels to 85 degrees
relative to the origin. What is the change in angle?
a. 245 degrees b. 75 degrees
c. 285 degrees b. 90 degrees

5. The LESS time Meb takes to finish a marathon, the _______ his average linear velocity will be.
a. higher b. lower

6. If Joe Bob swings a baseball bat 290 degrees in 0.75 seconds, what is the average angular velocity of
the swing?
a. 386.67 deg/s b. 217.50 deg/s
c. 0.0026 deg/s d. 290.00 deg/s

7. In the absence of external factors (such as friction or air resistance), the total momentum of a given
system remains constant.
a. True b. False
c. I don’t know

8. Based on The Law of Action & Reaction (Newton’s Third Law), when one body exerts a force an
another, the second body exerts a reaction force on the first that is equal in magnitude and opposite
in direction
a. True b. False
c. I don’t know
9. Which of the following statements is FALSE?
a. qualitative description cannot be detailed
b. kinetic chain is crucial for injury prevention Base runner
c. quantitative involve the use of numbers
d. to solve qualitative problems, it is essential to formulate questions regarding 15 m

the movement

10 m
10. A baseball player hits a triple to deep center field (Fig 2). As he is approaching third
base, he notices that the incoming throw to the catcher is wild, and he decides to
break for home plate. The catcher retrieves the ball 10 m from the plate and runs back Catcher
toward the plate at a speed of 5 m/s. As the catcher starts running, the base runner,
who is traveling at a speed of 9 m/s, is 15 m from the plate. Who will reach the plate first? Fig 2
a. Base runner b. Catcher
c. Same d. Cannot be calculated

11. Connor McGregor was hit in the face by a hand with an effective mass of 7.5 kg accelerating at 52
m/s2. If the impact lasts a total of 0.14 seconds, what was the impulse applied to his face?
a. 1.03 N·s b. 1.05 N·s
c. 2785.71 N·s d. 54.6 N·s

12. A high jumper has a mass of 75 kg and is falling at a peak velocity of 18 m/s just before landing on a
matt. If she comes to a complete stop on the matt, what was the impulse of the landing?
a. 4.17 N·s b. 0.24 N·s
c. 1350 N·s d. Cannot be calculated

13. Which of the following characteristics of a vector represents magnitude?

a. its angle of orientation
b. its length
c. its direction
d. All of these answers are correct.

14. When you are walking, which of the following types of force act parallel to the ground?
a. friction force
b. gravity force
c. ground reaction force
d. All of these answers are correct.

15. A Tour de France cyclist is pedaling at a ground speed of 15 m/sec. If he is cycling with a 5 m/sec
tailwind (a wind having same direction as cycling), which of the following is false regarding air drag?
[see fluid drag equation for hints]
a. the relative velocity of the air molecules acting on the cyclist is 10 m/sec
b. the air drag is quadrupled if he maintains the same ground speed into a 5 m/sec headwind
(opposing forward motion)
c. A 5 m/sec tailwind exerts a pushing or propulsive force on the cyclist when he rides at 15 m/sec,
as if he were a sail.
16. Jose Altuve of the Houston Astros hits a home run to center field against the New York Yankees. The
Yankees pitcher C.C. Sabathia threw a 42.47 m/sec fastball, and Altuve’s bat made contact with the
baseball, causing it to travel at 51.86 m/sec in the opposite direction. ESPN cameras recorded the
contact time between the bat and the ball as 0.0008 sec! Find the linear acceleration of the bat on
the ball.
a. 11,737.5 m/sec2
b. 145,095 m/sec2
c. 75.4 cm/sec2
d. 117,912.5 m/sec2

17. The vastus lateralis and vastus medialis are pulling on the quadriceps tendon and patella with forces
of 400 and 300 N, respectively, as pictured below. Find the magnitude of the net (or composite)
vector if the two muscles are pulling on the quadriceps tendon at an angle of 20°.
a. 500.00 N
b. 100.00 N
c. 689.58 N
d. 156.44

18. In order to achieve a higher running speed, world-class sprinters can produce ( ) than the
typical individual.
a. more work
b. longer stride lengths
c. higher stride rates
d. a and b
e. b and c

19. Maria is running around a turn on a track. She begins the turn at a velocity of 10 m/sec. In 1.5 sec
she turns 40° and is now running at 9.5 m/sec. Find her acceleration during this time period.
a. 10 m/sec2
b. 4.46 m/sec2
c. 6.69 m/sec2
d. 3.34 m/sec2

20. Force is an impetus that can cause a change in.

a. the velocity vector of an object
b. shape of an object
c. inertia
d. a and b
e. a, b, and c
21. If coordinates (in cm) for 2 consecutive frames (film speed = 500 frames/sec) for a football pass are
(-8,22) and (12,35), what is the rectilinear distance?
a. 15.20 cm
b. 23.85 cm
c. 33.0 cm
d. 36.62 cm

22. A large box slides across a frictionless surface with a velocity of 12 m/s and a mass of 4 kg, collides
with a smaller box with a mass of 2 kg that is stationary.  The boxes stick together. What is the
velocity of the two combined masses after collision?
a. 0 m/s
b. 4 m/s
c. 8 m/s
d. 12 m/s

23. Which of the following terms means "towards the front of the body"?
a. anterior
b. posterior
c. superior
d. inferior

24. Which of the following defines center of gravity?

a. intersection of the 3 cardinal planes
b. the point around which a body's weight is equally balanced regardless of body position
c. both intersection of the 3 cardinal planes and the point around which a body's weight is equally
balanced regardless of body position
d.) neither intersection of the 3 cardinal planes nor the point around which a body's weight is
equally balanced regardless of body position

25. Which of the following is/are scalar quantities?

a. force
b. mass
c. velocity
d. All of these answers are correct.

26. Janie is a fast-pitch softball pitcher. The distance from the center of rotation of her shoulder to the
center of gravity of the softball is 55cm. If it takes 0.12 seconds for the pitcher’s arm to move from
an angular position of 1800 to an angular position of 270 (pictured below), what is the angular
0

velocity of the arm during this time interval?

a. 750.00 deg/sec
b. 13.09 deg/sec
c. 412.5 m/sec
d. 7.20 m/sec
27. Find the rotary portion of muscle force pictured (resolve the force vector to find the component that
causes joint rotation). The muscle force is 250 N. The angle of pull = 70°
a. 250 N
b. 85.5 N
c. 234.92 N
d. 196.2 N

28. Trayveon Williams of the Aggie football team weighs 915 N. He takes a pitchout while traveling at a
horizontal velocity of 3 m/sec. 1.8 seconds later he is running at a horizontal velocity of 9.5 m/sec.
What was the horizontal force it took to achieve this?
a. 4829.2 N
b. 915 N
c. 1091.3 N
d. 336.8 N
e. 3304.2 N

29. Amanda is 5 ft. 2 in. tall and shoots a free throw at a 10 ft. high basket. The optimal projectile angle
of the shot for accuracy should be close to. (Assume Amanda does not have Inspector Gadget arms!)
a. 50°
b. 30°
c. 40°
d. optimal projectile angles are always 45°

30. Sam is a rearfoot striker with a body mass of 70 kg. His foot approaches the ground at a velocity of 4
m/sec before it strikes. Of course after landing (in stance phase) the foot has a velocity of 0 m/sec.
Sam runs with his shoe A or his shoe B. Shoe A has a collision time of 0.185 sec, and Shoe B has a
collision time of 0.175 sec. Which shoe has larger impact force?
a. A
b. B
c. Same

31. The center of gravity of Usain Bolt is calculated to accelerate an average of +4 m/sec2 during a 2 sec
time period early in a 200 m run. If his initial velocity was 2 m/sec, calculate the final velocity at the
end of the 2 sec period.
a. 3 m/sec
b. 9 m/sec
c. 10 m/sec
d. 16 m/sec
32. Oprah Winfrey walks 10 miles north and then 5 miles west. What is Oprah’s total displacement?
a. 11.2 miles b. 7.5 miles
c. 15 miles d. 12.5 mile

33. Lady Gaga is riding a bicycle ergometer set to a resistance of 20 N per meter (requires 20 N of force
to overcome friction every meter ridden). If she peddled the ergometer for 1km, how much work
was performed. (do not forget to convert km to m)
a. 20 J b. 200 J
c. 2,000 J d. 20,000 J

34. A basketball is released with an initial speed of 8 m/s at an angle of 60°. What is the vertical
components of the ball’s initial velocity
a. 8 m/s b. 4 m/s
c. 6.9 m/s d. 16 m/s

35. A volleyball is deflected vertically by a player in a game housed in a high school gymnasium where
the ceiling clearance is 10 m. If the initial velocity of the ball is 15 m/s, will the ball contact the
ceiling?
a. Yes b. No
c. I don’t know

36. A dancer performs a pirouette (spin) in which plane?

a. sagittal
b. frontal
c. transverse
d. longitudinal

37. What is one way you might increase your stability (balance)?
a. Lower the center gravity
b. Shorten the base of support
c. The line of the center gravity falls outside of the base of support
d. Lose weight

38. The frontal plane divides the body into equal ________.
a. right and left halves
b. front and back halves
c. top and bottom halves
d. medial and lateral halves

39. A 90 kg ice hockey player collides head-on with an 80 kg player. If the first player exerts a force of
450 N on the second player, how much force (magnitude) is exerted by the second player on the
first?
a. 450 N
b. 882 N
c. 784 N
d. 900 N
40. The score was tied 20–20 in the final 1987 AFC playoff game between the Denver Broncos and the
Cleveland Browns. During the first overtime period, Denver had the opportunity to kick a fi eld goal,
with the ball placed at a distance of 29 m from the goalposts. If the ball was kicked with the
horizontal component of initial velocity being 18 m/s and a flight time of 2 s, was the kick long
enough to make the field goal?

a. Enough b. No Enough
c. I don’t know

41. We film with a digital video camera a fast-pitch softball pitcher is throwing to home plate. The film
speed is 30 frames/sec. Here, we’ll assume that the shoulder joint is the axis of rotation and the
elbow is extended. Pitcher’s arm is 0.85 m long. His arm is in an absolute angular position of 150° at
frame 2 after we starting filming. On the next two consecutive frames, his arm is in a position of
180° and 220° respectively. Find the angular velocity and acceleration!

velocity= 1050 deg/s

acceleration= 4500 deg/s2
work attached below

42. During a goal-line stand, a 75-kg fullback

moving eastward with a speed of 10 m/s collides head-on with a 100-kg lineman moving westward
with a speed of 4 m/s. The two players collide and stick together, moving at the same velocity after
the collision. Determine the post-collision velocity of the two players.
velocity= 2m/s
work attached below