2.2.3 Mechanics - Dynamics

Question 1

What is Newton’s first law?

Answer 1

A body at rest remains at rest and a body in motion continues to move at constant velocity unless acted upon by an unbalanced external force

Question 2

What is Newton’s second law?

Answer 2

Force = mass x acceleration

Question 3

What is Newton’s third law?

Answer 3

Every reaction has an equal and opposite reaction

Question 4

What is the equation for lift?

(and what does each term mean)

Answer 4

L = 1/2 (rho)(V²)(S)(CL)

rho = density of the air

CL = coefficient of lift

S = area (Is the surface of the planview of the apparent wing, including the parts covered from the fuselage, engines and other

V = airspeed

Question 5

What is energy? (definition)

Answer 5

Energy is the capacity of something to do work.

Energy is a quality that a body has after work has been done on this body, The body can then do work on other bodies.

Question 6

What is the formula for Kinetic energy?

Answer 6

Question 7

What is the formula for Potential Energy?

Answer 7

Question 8

What does the Conservation of energy state?

Answer 8

In physics, the law of conservation of energy states that the total energy of an system remains constant - it is said to be conserved over time.

Energy can neither be created nor destroyed; rather, it transforms from one form to another

When energy transfers from one form to another, such as from Potential Energy to kinetic energy, work is done

Question 9

The SI unit for heat is the

Answer 9

Joule (J)

(Form of enery)

Question 10

What does BTU stand for?

Answer 10

British Thermal Unit

Question 11

In the imperial system, the unit of power is the __________

and in the metric system the unit is the ______

Answer 11

horsepower

Watt

Question 12

What is the formula for Momentum?

Answer 12

Momentum = mV

where m = mass

V = Velocity

Question 13

What is the equation for the conservation of momentum and what does the equation tell us

Answer 13

The equation tells us that the total momentum before the collision is equal to the total momentum after the collision

Question 14

What happens with collision of Billiard balls?

(Billiard balls = Snooker balls)

Answer 14

Sometimes kinetic energy is also conserved in a collison.

This happens when the bodies are so hard that there is very little deformation of the bodies in the actual collision process.

Billiard balls are an example and these collisions are known as elastic collisions.

Question 15

What is impulse?

Answer 15

Impulse = change in momentum

Question 16

What is rigidity in a Gyro?

Answer 16

Whilst small, the rotor of a gyroscopic instrument must rotate at a very high RPM.

Giving them inertia, also called rigidity and they maintain this alignment to a fixed point in space.

This basically happens to every rotating object: wheel, propeller etc

For example, this rigidity gives the moving bicycle its stability preventing it from falling over while riding it.

Question 17

What is precession in terms of a gyro?

Answer 17

When you apply a force to a point around the spinning rim of the gyro, the rotor will tilt as if the force was 90 degrees further in the direction of motion.

Question 18

Rate Gyro

(Angle of rotation)

(instrument_

Answer 18

Rate Gyro

Vertical axis gyro

Turn rate indicator

(To remember - rate of turn)

Question 19

Tied Gyro

(Axis of rotation)

(instrument on aircraft)

Answer 19

Tied Gyro

Horizontal axis of rotation

Heading indicator

(diagram in notes clearer) - tied end

Question 20

Earth gyro

(axis of rotation)

(aircraft instrument)

Answer 20

Earth gyro

vertical axis of rotation

Attitude indicator

(earth relation - how to remember)

Question 21

The weight (w) and the normal force (N) are ……….

Answer 21

equal to each other

Question 22

What are the 3 kinds of friction?

Answer 22

1. Static friction
2. Sliding friction
3. Rolling friction

Question 23

Which is higher, static friction of kinetic friction?

Answer 23

The coefficient of static friction, typically denoted as μ_s , is usually higher than the coefficient of kinetic friction.

The initial force to get an object moving is often dominated by static friction

note: kinetic friction = rolling friction or sliding friction

Question 24

The coefficient of sliding friction is typically denoted as μ_slide and is usually ______ than the coefficient of static friction

Answer 24

The coefficient of sliding friction is typically denoted as μ_slide and is usually less than the coefficient of static friction

Question 25

What is the formula for friction?

Answer 25

Question 26

Answer 26

0.4, 0.2