Quiz #9

Question 1

The study of the cause of motion in which all points on the object of interest move through the same displacement in the same time
- study of linear forces

Answer 1

linear kinetics

Question 2

Linear kinetics:
- helps identify why injuries occur and how to prevent them
- helps direct conditioning, training, and rehabilitation programs

Answer 2

importance from a biomechanical perspective

Question 3

Any interaction between two objects that causes or has the potential to cause acceleration
- measured in Newtons
- Properties: magnitude, direction, point of application, line of action

Answer 3

Force

Question 4

Types of forces

Answer 4

• non-contact = gravity
• contact = direct interaction of 2 or more objects (GRF, external forces, friction, fluid resistance, ect)

Question 5

Sketch that shows a defined system in isolation with all of the force vectors acting on the system

Answer 5

free body diagram

Question 6

Free body diagram:
- Forces acting on the body:

Answer 6

a) GRF
b) Friction
c) Fluid or air resistance
d) Gravity or body weight

Question 7

Identify the 4 external forces on a free body diagram

Answer 7

-From left to right-
1. Friction (at heel)
2. Ground reaction force (ball of foot)
3. Gravity (weight of body pulling down)
4. air resistance (at chest)

Question 8

• Direct application of newton’s 3rd law (action-reaction)
• Changes in magnitude, direction, and point of application during contact

Answer 8

Ground reaction force (GRF)

Question 9

Linear Kinetics:
- Ground reaction force
- measured with a force plate
- broken down into 3 components: _, _, _

Answer 9

1. vertical
2. medial-lateral
3. anterior-posterior

Question 10

Characteristic patterns:
- walking
- Bimodal (2 distinct peaks)
- vertical: _
- A/P: _

Answer 10

• vertical: 1-1.5 bw
• A/P: 0.15 bw

Question 11

Characteristic patterns:
- running
- Vertical: _
- A/P: _
- Passive peak (heel strike)
- Active peak (forefoot)

Answer 11

• Vertical: 2-5 bw
• A/P: 0.5 bw

Question 12

Know graph pattern characteristics for

Answer 12

• walking
• running
• jumping
• landing

Question 13

Know how to do Law of Cosine calculation

Answer 13

THETA = Cos^-1 ((a^2 - b^2 - c^2)/(-2bc))

Question 14

• Momentum relationship
• Changes the momentum of an object
• ZF = ma
• ZF = m(DetaV/DeltaT)
• ZFDeltaT = mDeltaV

Answer 14

impulse

Question 15

change in momentum

Answer 15

impulse

Question 16

impulse =

Answer 16

area under force - time curve

Question 17

• ZFDeltaT = mDeltaV

Answer 17

impulse-momentum relationship

Question 18

Ijump = Igrf - Iweight

Answer 18

jumping

Question 19

DeltaV = Ipropulsion - Ibrake

Answer 19

Walking/running