2.2.1 - Mechanics (Statics)

Question 1

What is the SI unit for mass?

Answer 1

the kilogram (kg) or slug

Question 2

What is 1 slug in kg?

Answer 2

1 slug = 14.59kg

Question 3

What is 1lb in N?

Answer 3

1lb = 4.448N

Question 4

What is the difference between mass and weight?

Answer 4

An object’s mass is a quantity of matter making it up; which will never change.
An object’s weight is a measure of the gravitational force exerted on it (which changes depending where it is in the universe)

Question 5

What is the formula for weight?

Answer 5

W = mg

Question 6

What is 2.2lbs in kg?

Answer 6

2.2lbs = 1 kg

Question 7

What is 1kW equal to in BTU?

Answer 7

3412 BTU/Hour

Question 8

What is the numerical value for gravitational force?

Answer 8

9.8

Question 9

What is the equation for moment?

Answer 9

Moment = Force x distance

Question 10

What does the sum of clockwise moments equal?

Answer 10

The sum of anticlockwise moments

Question 11

What is a couple?

Answer 11

A pair of forces acting in equal but opposite directions (eg, a steering wheel)

Question 12

What is Sin(90)?

Answer 12

1

Question 13

What is the equation for torque?

Answer 13

t=F x d x sin(ϴ)

Question 14

How do you calculate the scale reading on a torque wrench when using an extension?

Answer 14

Scale reading = Specified torque x (length/length + extension)

Question 15

What is a Centroid?

Answer 15

The centre of mass of an object.

Question 16

What are the three aircraft weighing methods?

Answer 16

• Weighbridge Scales
• Hydrostatic Weighing Units
• Electronic Weighing Equipment

Question 17

How many readings should be made when weighing an aircraft?

Answer 17

2

Question 18

What are the two categories of quantities in physics?

Answer 18

Vectors and Scalars

Question 19

What is a vector?

Answer 19

A quantity that is fully described by both magnitude and direction

Question 20

What is a scalar?

Answer 20

A quantity that is fully described by magnitude alone

Question 21

What is strain?

Answer 21

A measure of the deformation of a material under a load. The ratio of the amount of deformation to it’s original size.

Question 22

What are the two primary structural stresses?

Answer 22

Tension and Compression

Question 23

What is tension?

Answer 23

A primary stress that tries to pull a body apart (a weight on a chain)

Question 24

What is compression?

Answer 24

A primary stress that tries to squeeze parts together (a weight on a post)

Question 25

What is shear?

Answer 25

Forces that try to slide a body apart.

Question 26

What is torsion?

Answer 26

A twisting force. Tensile stress acts diagonally across a structural member that is twisted.

Question 27

What is bending?

Answer 27

A bending force tries to pull one side of a body apart while at the same time squeezes the other side together.

Question 28

What is the formula for stress?

Answer 28

Stress = Force/Area

Question 29

What is Hooke's Law?

Answer 29

F=Ke (K being the spring constant) (e is the extention)

Question 30

What is the elastic limit?

Answer 30

Where Hooke's Law does not apply. It is known as the limit of proportionality. Permanent deformation occurs after this limit.

Question 31

What is the formula for strain?

Answer 31

Strain = Deformation/Original length

Question 32

What is the Bulk Modulus?

Answer 32

It gives the change in volume of a solid substance as the pressure on it is changed.

Question 33

What is Poisson's Ratio?

Answer 33

The ratio of transverse strain to the axial strain. When a member is stressed in tension, it's length increases (axial strain) and it's width decreases (transverse strain).

Question 34

What is the equation for density?

Answer 34

Density = Mass / Volume

Question 35

What is the equation for pressure?

Answer 35

Pressure = Force / Area

Question 36

What is 1Pa?

Answer 36

A Pascal (1N of force on 1M^2). 1/100,000Bar (incredibly low pressure)

Question 37

What is an Isobar?

Answer 37

A line on a weather map joining together places of equal atmospheric pressure.

Question 38

What is Pascal's Law?

Answer 38

Any force applied to a contained fluid is transmitted in all directions throughout the fluid and at right angles to the containing surfaces.

Question 39

What is the formula for the pressure on an object submerged in a fluid?

Answer 39

P = pgh

Question 40

What happens to pressure with increasing depth in a fluid?

Answer 40

It increases

Question 41

What is Archimedes' Principle?

Answer 41

A body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid

Question 42

What is the formula for Pressure on an object submerged in a fluid?

Answer 42

Pressure = p (rho) x g x h (rho is density of fluid)

Question 43

What is the formula for the volume of a sphere?

Answer 43

V = 4/3 pi x r^3

Question 44

The unit of Young's module are that of...

Answer 44

Pressure

Question 45

What is the height of mercury required to give 1 bar?

Answer 45

760mm (1 bar is almost atmospheric pressure)

Question 46

For the CGS (centimetre-gram-second) system, what is the force?

Answer 46

The 'Dyne' - which produces an acceleration of 1cm/s^2 for a mass of gram

Question 47

What is the opposite of a tensile force?

Answer 47

Compression (tension is to be pulled apart)

Question 48

What is the difference between a tied gyro and an earth gyro?

Answer 48

Both are free to rotate in 3 axis, both have a fixed point but an Earth gyro is specifically 'tied' to an earth reference point

Question 49

What is the coefficient of limiting friction?

Answer 49

The point at which an applied force overcomes friction and an object begins to move