Unit 1: Basic Concepts

Question 1

What are the SI units for length, time, mass, temperature and angle?

Answer 1

Length = metres (m)
Time = seconds (s)
Mass = kilograms (kg) 
Temp = Kelvin (K) 
Angle = radians (rad)

Question 2

Give 2 examples of derived units

Answer 2

Newtons (N)

Pascals (Pa)

Question 3

What is the multiplication factor for milli?

Answer 3

10(-3)`

Question 4

How many radians are in 360 degrees?

Answer 4

2π

Question 5

How are rectangular coordinates labelled?

Answer 5

In terms of x, y & z axis’ (perpendicular to each other)

Question 6

Name the 3 planes used to describe the human body?

Answer 6

Sagittal plane
Coronal plane
Transverse plane

Question 7

When are polar coordinates more useful than rectangular coordinates?

Answer 7

Studies of circular objects and when angles and rotations are important

Question 8

What are the two forms of motion?

Answer 8

Linear & rotatory

Question 9

What is the deference between vectors & scalars?

Answer 9

Scalars = magnitude only 
Vector = magnitude + direction

Question 10

Define velocity

Answer 10

Rate of change of displacement

Question 11

Define acceleration

Answer 11

Rate of change of velocity

Question 12

What 2 effects do forces have on an object?

Answer 12

Change position of object in space + deform the shape of object

Question 13

Name a simple way of measuring forces

Answer 13

Spring balance

Question 14

What is a newton in terms of SI units?

Answer 14

1 kgms(-2)

Question 15

When are bodies considered to be at static equilibrium?

Answer 15

When not moving or moving at a constant velocity (i.e. not accelerating)

Question 16

What is translational equilibrium?

Answer 16

Static equilibrium along straight lines

Question 17

What is Newton’s third law?

Answer 17

Every action has an equal & opposite reaction

Question 18

Define mass

Answer 18

Quantity of matter of which a body is composed

Question 19

Define weight

Answer 19

Force of grvity acting on a body

Question 20

What is denisty (p)?

Answer 20

Mass per unit volume (m/v)

Question 21

What is the equation for weight?

Answer 21

W = mg

Question 22

What is the relationship between centre of mass & centre of gravity?

Answer 22

Centre of mass = centre of gravity if their is gravity (if no gravity there is only a centre of mass)

Question 23

Define pressure

Answer 23

Force exerted per unit area (P = F/A)

Question 24

What are the units of pressure?

Answer 24

Pascals

Question 25

What is the moment (torque) of a force?

Answer 25

The tendency of a force to produce rotation about an axis

Question 26

What is the equation for moments?

Answer 26

M = Fd

Question 27

What are the units of moments?

Answer 27

Newton metres (N m)

Question 28

What is rotational equilibrium?

Answer 28

When th sum of all the external moments acting on a body is equal to zero

Question 29

Name the component parts of a lever?

Answer 29

Rigid bar
Fulcrum
Effort force
Resistance force

Question 30

How is mechanical advantage calculated?

Answer 30

MA = Effort arm/Resistance arm

Question 31

How can it be determined if a system is working at a mechanical advantage or disadvantage?

Answer 31

MA > 1 = mechanical advantage

MA < 1 = mechanical disadvantage

Question 32

Describe a first class lever

Answer 32

Fulcrum is located between the effort and resistance

Question 33

Describe a second class lever

Answer 33

Resistance located between the effort and the fulcrum (e.g. wheelbarrow)

Question 34

Which lever classes always work at a mechanical advantage or disadvantage?

Answer 34

1st class = either
2nd class = always advantage
3rd class = always disadvantage

Question 35

Describe a third class lever

Answer 35

Effort is located in between resistance and the fulcrum (e.g. tweezers)

Question 36

What do all the angles in a triangle add up to?

Answer 36

180 degrees