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3 years ago

The voltage across a device and the current through it are:

Engineering

2 answers:

Strike441 [17]3 years ago

7 0

Answer: Charge, Q= 22.131 columbs

Power, P = 196.65 Watts

Explanation:

I(t) = 10( 1 - e(-0.5t)) A

I = dQ/dt

dQ = 10( 1 - e(-0.5t))dt

Integrating we have

Q = 10t - (20/(-0.5))e(-0.5t)

taking the value of t at 1s

we have,

Q = 10 + 20e(-0.5)

Q = 10 + 20/1.6487

Q = 10 + 12.131

Q = 22.131 Columbs

(b) Power

Power = voltage x current

Power = 5cos(2t) x 10(1 - e(-0.5t))

Power at t= 1, we substitute t=1

Power = 5cos(2) x 10(1 - e(-0.5))

Power = 5(0.9995) x 10(1 - 0.60654)

Power = 39.35 x 4.9975 = 196.65 Watts

Power = 196.65 Watts

butalik [34]3 years ago

3 0

Answer:

attached below

Explanation:

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marysya [2.9K]

GPS device details are given below.

Explanation:

Even a simple GPS unit has a wide range of settings and features. Because every unit’s operation varies, this article won’t provide step-by-step details. Read the owner's manual to familiarize yourself with it.. If you’d like additional help, you can also sign up for a GPS navigation class at an REI store.

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3 years ago

Consider the velocity boundary layer profile for flow over u flat plate to be of the form u = C_1 + C_2 y. Applying appropriate

ra1l [238]

Answer:

The result in terms of the local Reynolds number ⇒ Re = [μ_∞ · x] / v

Explanation:

See below my full workings so you can compare the results with those obtained from the exact solution.

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3 years ago

All air-conditioning units must be grounded electrically to

Tpy6a [65]

Answer:

Prevent electrical shock

Grounding is a non current carrying conductor mainly used to guard against hazards due to leakage in electric circuits

Explanation:

The grounding refers to the connection of an electrical equipment exposed metallic parts to the ground to serve as a source of current flow in the event of an insulation failure will cause the fuses to trip thereby isolating or removing electric power from the device

Grounding also prevents the accumulation of static electricity which can be a source of fire in inflammable areas.

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3 years ago

How do engineering approach their work (how do they do to solve the problem).

Romashka-Z-Leto [24]

engineering approach their work by finding new solutions to their problems. like if two things dont go together in an invention, they will find another way

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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

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