Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Engineering physics > Flashcards

Engineering physics Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Rotational dynamics

What effects the flywheel KE

[4]

A
  1. mass
  2. angular velocity
  3. friction
  4. spoked - mass spread out to the side
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Rotational dynamics

three uses of flywheel

A
  1. regenerative breaking
  2. wind turbine
  3. smoothing out torque/ angular v.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how to convert any
quantity
angular -> linear

A

multiply by radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Thermodynamics

What does +ve Q means

A

energy transfered into the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Thermodynamics

What does +U mean

A

increased avg. KE of particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Thermodynamics

What does +WD mean

A

work done by the particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thermodynamics

what is the area underneath p-v graph

A

Work done by gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Thermodynamics

What is constant in isothermal process

A

internal energy / temp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Thermodynamics

What is constant in adiabatic processes ?

A

heat energy of system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thermodynamics

Describle the 4 steps to ideal engine cycle

A

Induction - constant Pa expansion
Expansion - adiabatic
Compression - adiabatic
exhaust - constant Pa compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Thermodynamics

describle the induction step of ideal engine

A
  1. fuel mixture in
  2. volume increases at constant Pa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Thermodynamics

describle expansion stroke of ideal engine

A
  1. valves closed
  2. piston push down to compress gas
  3. spark generated
  4. heat transfered to system
  5. Inc. U => Inc. T and Inc. Pa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Thermodynamics

Describle power stroke

A
  1. net WD by gas to push piston
  2. volume increases
  3. Temp decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Thermodynamics

Differences between
real and ideal
engine cycle

A
  1. need induction and exhaust stroke
  2. rounded corners - valve takes time
  3. heating/cooling cannot occur at constant vol.
  4. not ideal gas
  5. fuel may not completely combust
  6. mas pressure is lower
  7. compression/expansion not completely adiabatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Thermodynamics

Difference between
petrol and diesel
engine

A
  1. only draws air in induction stroke
  2. fuel introduced during expansion stroke
  3. no spark needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Thermodynamics

Why is there less
work output
in real engine

A
  1. smaller area of loop
  2. area of pumping loop needed subtraction
  3. friction between surfaces
  4. energy used in pumping gas + valve op.
17
Q

Thermodynamics

define 2nd law of thermodynamics

A

the need for engine to operate between a source and a sink

18
Q

Thermodynamics

How to maximise Qh and WD

2nd law of thermodynamcis

A
  1. CHP - combine heat and power
  2. reduce friction
19
Q

Thermodynamics

What is the purpose of refridgerator

A
  • abstract as much heat as possible from cold place
  • maximise Qc
20
Q

Thermodynamic

what is the purpose of heat pump

A
  • deliver as much as heat to hot place
  • maximise Qh
21
Q

Thermodynamics

Eq. of thermal efficiency

A

indicated / Qh

22
Q

Thermodynamics

Eq. of mechanical efficiency

A

brake / indicated

23
Q

Thermodynamics

Eq. of overall efficiency

A

mechanical x thermal

brake / Qh

24
Q

Define input power

A

indicated power (WD) +
output power to sink (Qh)

25
Q

Thermodynamics

How to cal. Indicated power

A

A(loop) * no. of piston * frq of cycle

26
Q

Thermodynamics

Indicated power eq.

A

brake power + frictional power

27
Q

how many rotations per cycle

A

2

28
Q

Describle thermal efficiency

A

how well the calorific value of fuel is converted into work inside engine

29
Q

Describle mechanical efficiency

A

work/power used to overcome friction/viscocity inside engine and operate valves, water and oil pumps.

30
Q

Thermodynamics

why is it not advised to operate above optimal speed

A
  1. thermal efficiency decreases
  2. friction increases at higher speed
  3. work against greater viscosity
31
Q

Thermodynamics

Why is there less WD isothermally than adiabatic

A
  1. adiabatic curve is steeper to reach the same volume
  2. greater area under the curve
  3. so more WD

Physics (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions