Class test 2 revision Flashcards Preview

Biomechanics > Class test 2 revision > Flashcards

Flashcards in Class test 2 revision Deck (26):
1

Newtons first law

A body continues in a state of rest or constant velocity unless acted upon by an external force

2

Newtons second law

Law of acceleration- the rate of change of motion (acceleration) of a body is proportional to the force acting on it and is in the direction that the force acts

3

Newtons third law

Law of action- reaction
For every action, there is an equal and opposite reaction

4

What is mass?

Quantity of matter a body possesses

5

What is force?

Mass x acceleration

6

What is the amount f force necessary to accelerate a mass of 1kg at 1m/sec

1 newton

7

What is kinematics ?

Describes motion in terms of time and space

8

What is kinetics ?

Examines the forces

9

What is Newton's law of gravitation?

Every particle in the universe attracts every other particle with an attractive force

10

A body behaves as though all of its mass was concentrated at the centre of gravity. True or false

True

11

What do free body diagrams show?

Show all external forces
Forces drawn as vectors (direction and size)

12

What is equilibrium?

Describes the state of a system that is not changing its speed or direction

13

What is static equilibrium?

A body at rest

14

What is dynamic equilibrium?

A body that has unchanging speed or direction

15

What is stability?

Refers to the state of equilibrium
The ability of a body to maintain its beginning static equilibrium posture

16

What is the base of support?

The area made with the part of the body touching supporting surface

17

What is stable equilibrium?

Small perturbation applied- tends to return to its original position

18

What is unstable equilibrium?

Small perturbation applied- tends to accelerate away

19

What is neutral equilibrium?

Neither returns or accelerates

20

What happens to the centre of mass in a human body as a projector?

The centre of mass will follow path regardless of changes of body configuration

21

If an athlete wants to change direction quickly, should they have a small or large base of support?

Small

22

When is an athlete most stable?

Low centre of mass
middle of base of support

23

Describe external forces

Act on objects as a result of interaction with surrounding environment
Contact/surface forces- occur between objects in contact
Non contact forces e.g. gravity

24

Describe internal forces

Act within the object
Do not accelerate the body

25

What is an eccentric force?

A force whose line of acion doesn't pass through the centre of gravity
Changes both angular and linear motion

26

What is a concentric force?

A force whose line of action passes through the centre of gravity of the body on which it acts
Causes a change in linear motion