Biomechanics

Question 1

What are internal forces?

Answer 1

forces that arise within the human body (ex. contraction of a muscle generates a force moving a bone)

Question 2

What are external forces?

Answer 2

forces that originate outside the object or body (ex. gravity, wind, friction)

Question 3

What is Newton’s 1st Law of Motion?

Answer 3

the law of inertia: a body in motion tends to stay in motion, and a body at rest tends to stay at rest, unless acted upon by an external force

Question 4

What is Newton’s 2nd Law of Motion?

Answer 4

the law of acceleration: F=ma

part 1: the effect of magnitude of the applied force (ex. if a large force is applied to a ball, it will experience a large change in the rate at which it is moving)

part 2: the mass of the object being hit (ex. if a baseball and a basketball are hit at the same force, the baseball will have a faster acceleration due to it’s smaller mass)

Question 5

What is Newton’s 3rd Law of Motion?

Answer 5

the law of action-reaction: for every action there is an equal and opposite reaction

Question 6

What does the Conservation of Energy state?

Answer 6

energy can not be created or destroyed, but can be converted into other forms

Question 7

What are the 7 principles of biomechanics?

Answer 7

stability, production of maximum force, production of maximum velocity, impulse-momentum relationship, direction of application of the applied force, production of angular motion, conservation of angular momentum

Question 8

Explain Principle 1: Stability

Answer 8

the quality, state, or degree of being stable and capable of resisting a change in motion

Question 9

Explain Principle 2: The Production of Maximum Force

Answer 9

requires the use of all possible joint movements that contribute to the task’s objective

Question 10

Explain Principle 3: The Production of Maximum Velocity

Answer 10

requires the use of the joints in order from largest to smallest

Question 11

Explain Principle 4: The Impulse-Momentum Relationship

Answer 11

in the absence of external forces, the total momentum of a given system remains constant. as well, any change in momentum is equal to the impulse that produces it, for example an equal force over less time produces more momentum

Question 12

Explain Principle 5: The Direction of Application of Applied Force

Answer 12

movement usually occurs in the direction opposite that of the applied force

Question 13

Explain Principle 6: Production of Angular Motion (torque)

Answer 13

produced by the application of a force acting at some distance from an axis, by torque

Question 14

Explain Principle 7: The Conservation of Angular Momentum

Answer 14

constant when an individual or object is free in the air

Question 15

What is the moment of inertia?

Answer 15

an object or body’s resistance to change in it’s rate of angular motion

Question 16

What is impulse?

Answer 16

the application of a force over a period of time

Question 17

What is momentum?

Answer 17

the quantity of motion contained within an object/body (mass x velocity)

Question 18

What is velocity?

Answer 18

the rate and direction of motion of an object/body

Question 19

What is angular momentum?

Answer 19

the quantity of angular motion contained within an object or body

Question 20

What is angular velocity?

Answer 20

quantitative expression of the amount of rotation a spinning object undergoes per unit of time

Question 21

What is centre of mass?

Answer 21

the imaginary middle point around which the mass of an object or person is balanced

Question 22

What is a base of support?

Answer 22

the supporting area beneath an object/body

Question 23

What is balance?

Answer 23

an even distribution of mass enabling some one/thing to remain steady

Question 24

What is mass?

Answer 24

the quantity of matter contained within an object/body

Question 25

What is the Law of Conservation of Momentum?

Answer 25

the total angular momentum of a rotating body remains constant if net torque acting on it is zero

Question 26

What is a static system?

Answer 26

the branch of mechanics that studies object or bodies in a state of constant, unchanging motion
(ex. diver jumps off a board and accelerates downwards at 9.91m/s)

Question 27

What is a dynamic system?

Answer 27

the branch of mechanics that studies changes in the motion of objects/bodies as a result of forces

Question 28

How is a 1st class lever set up?

Answer 28

axis of rotation is located between the effort and the load

Question 29

How is a 2nd class lever set up?

Answer 29

the load is between the effort and the axis of rotation

Question 30

How is a 3rd class lever set up?

Answer 30

the effort is found between the axis of rotation and the load