CE 10224A - Science for CE (Physics) Flashcards Preview

Chem Eng - Y1.S1 > CE 10224A - Science for CE (Physics) > Flashcards

Flashcards in CE 10224A - Science for CE (Physics) Deck (17)
Loading flashcards...
1

What are the 2 branches of dynamics?

- Kinematics (the study of the motion of point masses or rigid bodies. Focuses on calculating position, displacement, velocity and acceleration (not the forces causing them)

- Kinetics (the study of the forces that produce or change motion)

2

What are the types of friction?

Static frictional force, Fs - the force, opposing direction of motion and resulting in a static condition.

Kinetic friction, Fk - frictional force opposing motion as the object is moving.

3

How is static friction calculated?

𝐹𝑠 = πœ‡s𝐹Ν

Where:

Fs is static friction
πœ‡s is coefficient of static friction
FN is the normal force

4

How is kinetic friction calculated?

πΉπ‘˜ = πœ‡k𝐹N

Where:

Fk is kinetic friction
πœ‡k is coefficient of kinetic friction
FN is the normal force

5

In terms of friction coefficient, what causes an object to remain stationary?

When kinetic frictional force is less than force of static friction.

6

How is drag force calculated?

𝐷 = 1/2πΆπœŒπ΄π‘£^2

Where:
D is drag force
C is the drag coefficient
𝜌 is fluid density
A is cross-sectional surface area perpendicular to v
v is fluid velocity

7

How is centripetal force calculated?

𝑭𝒄 = π’Žπ’—πŸ / 𝒓

8

How is velocity and angular velocity calculated?

𝑣 = 2πœ‹π‘Ÿ / 𝑇

𝑣 = 2πœ‹π‘Ÿπ‘“

𝑣 = πœ”π‘Ÿ

πœ” = 2πœ‹ / 𝑇

9

How is centripetal acceleration calculated?

𝒂𝒄 = 𝝎^πŸπ‘Ÿ

𝒂𝒄 =𝒗^𝟐 / 𝒓

10

How are forces analysed in non-uniform circular motion?

If πΉπ‘‘π‘œπ‘‘ is acting at an angle, then this force causes a non-uniform circular motion


Analysis into x, y-axis components:

- There's a force directed towards the centre of the circle causing the centripetal acceleration, 𝒂𝒄

- A tangential force causes a tangential acceleration called 𝒂𝒕𝒂𝒏.

These accelerations are perpendicular to one another.

11

For non - uniform circular motion, how is total acceleration and angular acceleration calculated?

𝒂𝒄 = 𝝎^πŸπ‘Ÿ

𝒂𝒕𝒂𝒏 = 𝒅𝒗/𝒅𝒕 = π‘Ÿ π’…πŽ/𝒅𝒕

𝒂𝒕𝒐𝒕 = (𝒂𝒄^2 𝟐+𝒂𝒕𝒂𝒏^2)^1/2



π’‚π’‚π’π’ˆ= π’…πŽ/𝒅𝒕
= (πŽπŸβˆ’πŽπŸ) / (π’•πŸβˆ’π’•πŸ)

12

How are angular and tangential accelerations related?

𝒂𝒕𝒂𝒏 = π‘Ÿ*𝒂 π’‚π’π’ˆ

13

What's centrifugal force?

Ff, a β€˜β€™ reactive’’ force acting upon a body due to rotation, and on the opposite direction of the centripetal force, at an equal magnitude, away from the centre of rotation.

14

What's β€˜β€™apparent’’ centrifugal force?

Fapp, a force which pushes the object away from the centre of rotation.
This is not part of any interaction, but it is the objects inertia.

15

How is work done calculated?

π‘Š = πΉπ‘π‘œπ‘ πœƒ(π‘₯𝐡 βˆ’ π‘₯𝐴)

π‘Š = 𝑃(𝑉2 βˆ’ 𝑉1)

16

How is gravitational potential energy calculated?

[E = mgh]

U = mg(h2-h1)

17

How is kinetic energy calculated?

E = mv^2/2