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3 years ago

How do you distinguish the difference between drag and lift forces?

Engineering

1 answer:

kumpel [21]3 years ago

6 0

Answer Explanation :

LIFT FORCE:

Lift force is that force which acts right angles to the direction of motion
Lift forces is produced through air
Lift forces is created by difference in air pressure
force on wings of bird is an example of lift force

DRAG FORCE:

Drag force is that force which act opposite to the direction of motion
Drag is caused by friction and differences in air pressure
Skydiving is an example of drag force

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Discuss in detail the following methods used to redistribute income and wealth in cash grants?

aev [14]

Answer:

Redistribution of income and wealth is the transfer of income and wealth (including physical property) from some individuals to others through a social mechanism such as taxation, welfare, public services, land reform, monetary policies, confiscation, divorce or tort law.

-The term typically refers to redistribution on an economy-wide basis rather than between selected individuals.

Interpretations of the phrase vary, depending on personal perspectives, political ideologies and the selective use of statistics.

-It is frequently heard in politics, usually referring to perceived redistribution from those who have more to those who have less. Occasionally, however, it is used to describe laws or policies that cause opposite redistribution that shift monetary burdens from low-income earners to the wealthy.

The phrase is often coupled with the term class warfare, with high-income earners and the wealthy portrayed as victims of unfairness and discrimination.

Redistribution tax policy should not be confused with predistribution policies. "Predistribution" is the idea that the state should try to prevent inequalities from occurring in the first place rather than through the tax and benefits system once they have occurred. For example, a government predistribution policy might require employers to pay all employees a living wage, not just a minimum wage, as a "bottom-up" response to widespread income inequalities or high poverty rates.

Many alternate taxation proposals have been floated without the political will to alter the status quo. One example is the proposed "Buffett Rule", which is a hybrid taxation model composed of opposing systems, intended to minimize the favoritism of the special interest tax design.

7 0

2 years ago

A right triangle has a height of 20 centimeters and a base of 10 centimeters. What is the área of the triangle

zmey [24]

Answer:

100 cm

Explanation:

...........................

6 0

3 years ago

Question 7.1: Two possible overhead valve combustion chambers are being considered – the first has two valves; the second has fo

AleksandrR [38]

Answer:

1) The adoption of the second design we can see that the total valve perimeter is increased by 60.8%

2) Increase in flow are : 29%

3) Additional benefits in using 4 valves per cylinder:

a)For the purpose of controlling the combustion process, the inlet valves will give more flexibility

b) There is a larger valve throat areas for the flow of gas

Explanation:

1) Perimeter of the first possible overhead valve combustion chamber with two valves:

P₂ = πd = π × 23 = 72.26mm

Perimeter of the second possible overhead valve combustion chamber with four valves:

P₄ = π2d = π × 18.5 × 2 = 116.24 mm

If second design is adopted, percentage increase = ((P₄ - P₂)/P₂)×100

= ((116.24 - 72.26)/72.26)×100 = 0.6086 ×100 = 60.86%

Therefore, the total valve perimeter is shown to have increased by 60.8%

2) Formula for flow Area (A) = P × L = πkd²

Area of the first possible overhead valve combustion chamber with two valves: A₂ = πkd² = πk(23)² = 1662k mm²

Area of the first possible overhead valve combustion chamber with four valves: A₄ = πkd² = 2πk(18.5)² = 2150k mm²

The percentage increase in flow area: ((A₄ - A₂)/A₄)×100 = ((2150 - 1662)/2150)×100 = 29%

3) The additional benefits of using are:

a) For the purpose of controlling the combustion process, the inlet valves will give more flexibility

b) There is a larger valve throat areas for the flow of gas

7 0

3 years ago

A 50 Hz, four pole turbo-generator rated 100 MVA, 11 kV has an inertia constant of 8.0 MJ/MVA. (a) Find the stored energy in the

raketka [301]

Given Information:

Frequency = f = 60 Hz

Complex rated power = G = 100 MVA

Intertia constant = H = 8 MJ/MVA

Mechanical power = Pmech = 80 MW

Electrical power = Pelec = 50 MW

Number of poles = P = 4

No. of cycles = 10

Required Information:

(a) stored energy = ?

(b) rotor acceleration = ?

Answer:

(a) stored energy = 800 Mj

(b) rotor acceleration = 337.46 elec deg/s²

Explanation:

(a) Find the stored energy in the rotor at synchronous speed.

The stored energy is given by

$E = G \times H$

Where G represents complex rated power and H is the inertia constant of turbo-generator.

$E = 100 \times 8 \\\\E = 800 \: MJ$

(b) If the mechanical input is suddenly raised to 80 MW for an electrical load of 50 MW, find rotor acceleration, neglecting mechanical and electrical losses.

The rotor acceleration is given by

$P_a = P_{mech} - P_{elec} = M \frac{d^2 \delta}{dt^2}$

Where M is given by

$M = \frac{E}{180 \times f}$

$M = \frac{800}{180 \times 50}$

$M = 0.0889 \: MJ \cdot s/ elec \: \: deg$

So, the rotor acceleration is

$P_a = 80 - 50 = 0.0889 \frac{d^2 \delta}{dt^2}$

$30 = 0.0889 \frac{d^2 \delta}{dt^2}$

$\frac{d^2 \delta}{dt^2} = \frac{30}{0.0889}$

$\frac{d^2 \delta}{dt^2} = 337.46 \:\: elec \: deg/s^2$

(c) If the acceleration calculated in part(b) is maintained for 10 cycles, find the change in torque angle and rotor speed in revolutions per minute at the end of this period.

The change in torque angle is given by

$\Delta \delta = \frac{1}{2} \cdot \frac{d^2 \delta}{dt^2}\cdot (t)^2$