Lecture 13-14 - Biomechanics

Question 1

What are the 3 ways the body moves?

Answer 1

1. Body moving itself in different mediums and using implements and projectiles (gymnastics, diving, wrestling)
2. Body moving projectiles in different mediums (balls)
3. body moving implements in different mediums (racquets, sticks)

Question 2

What is Newton’s first law?

Answer 2

The Law of Inertia -> a body will remain at rest and a body will remain in motion unless acted on by an external force, Inertia is the reluctance to change

Question 3

How is Inertia measured?

Answer 3

by how much mass a body has

Question 4

what is mass?

Answer 4

a measure of the quantity of matter in an object

remains constant everywhere in the universe

Question 5

What is weight?

Answer 5

• gravitational attraction between two objects
• larger mass = larger gravitational attraction
• different throughout the universe
• weight is a measurement of force

Question 6

What is centre of mass?

Answer 6

centre of gravity

• point at which body’s mass is equally distributed
• point about which body rotates in free space
• balance point of the obdy
• can be outside the body

Question 7

What is it called when the body is in a “constant state” of motion (stillness of movement)?

Answer 7

Velocity

Question 8

What is the change in velocity called? and why would this change happen?

Answer 8

Acceleration (which can be either positive or negative) this would happen if a force changed it.

Question 9

What is force?

Answer 9

any cause that produces a change in the state of motion (or shape) that changes the acceleration of the body

Question 10

What is required to change motion?

Answer 10

force

Question 11

In what form is force initiated by the body?

Answer 11

muscle contraction

Question 12

What are 4 types of motion caused by the application or force?

Answer 12

1. No displacement
2. Linear displacement
3. Rotational (angular) displacement
4. Displacement to stationary (motion to no motion)

Question 13

What is no displacement?

Answer 13

when a force is put on something yet the centre of mass remains of the base

Question 14

What is linear displacement?

Answer 14

when a force passes directly through the centre of mass, the mass wil move forward or backward and be directly outside of the base

Question 15

What is Rotational (or angular) displacement?

Answer 15

• when an off centre force produces movement
• the further off centre the greater rotation and less linear displacement
• influenced by force and the distance from the force is applied from

Question 16

What is torque?

Answer 16

force times the lever arm(distance)

Question 17

What is displacement to stationary?

Answer 17

motion to motionless

• energy is absorbed or dissipated over time
• rolls for example

Question 18

What is human motion caused by?

Answer 18

force

Question 19

What is Newton’s 2nd Law?

Answer 19

Law of Acceration. acceleration is directlyh proportional to the force causeing it

Question 20

What is the formula for force?

Answer 20

force = mass x acceleration

Question 21

If mass is the same what does greater force equal?

Answer 21

greater acceleration

Question 22

What is momentum?

Answer 22

mass x velocity (ship, bullet, train)

Question 23

What is Newton’s 3rd Law?

Answer 23

Law of Action/Reaction: every action has an equal, opposite and concurrent reaciton, ground reaction force = matching force