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3 years ago

Why there is no inductive reactance in dc circuits

1 answer:

4 0

when voltage source is connected across an ideal inductor, the current through it is limited by self induced EMF( N.d(phi)/dt).. This EMF opposes its cause by Lenz's law.

When steady dc supply is connected, there is no change of flux and hence no induced EMF is developed and inductive reactance offered to steady DC supply is zero.

At the same time this induced EMF is proportional to rate of change of magnetic flux/voltage, hence the inductive reactance offered is also proportional to frequency of voltage source.

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A small object with mass 1.30 kg is mounted on one end of arod

Julli [10]

Answer:

(a) $I_{system} = 1.014\ kg.m^{2}$

(b) $\tau = 0.0179\ N-m$

Solution:

As per the question:

Mass of the object, m = 1.30 kg

Length of the rod, L = 0.780 m

Angular speed, $\omega = 5010\ rev/min$

Now,

(a) To calculate the rotational inertia of the system about the axis of rotation:

Since, the rod is mass less, the moment of inertia of the rotating system and that of the object about the rotation axis will be equal:

$I_{system} = ML^{2} = 1.30\times (0.780)^{2} = 0.791\ kg.m^{2}$

(b) To calculate the applied torque required for the system to rotate at constant speed:

Drag Force, F = $2.30\times 10^{- 2}\ N$

$\tau = FLsin\theta 90 = 2.30\times 10^{- 2}\times 0.780\times 1 = 0.0179\ N-m$

3 0

3 years ago

Metodo medible que no altera la composicion quimica de la materia o cuerpo?

SCORPION-xisa [38]

Answer:

Las propiedades físicas, como la dureza y el punto de ebullición, y los cambios físicos, como la fusión o la congelación, no implican un cambio en la composición de la materia.

Explanation:Creo que es correcta

3 0

3 years ago

Which statement best answers the question, "Why is copper a good conductor of electricity"?

balandron [24]

The answer is the letter A.

5 0

3 years ago

A competitive go-cart driver is traveling 32 m/s. He sees a caution flag go up, so he slows at a rate of -1.5 m/s^2 in 10.8 s. W

Svetllana [295]

Answer:

15.8 m/s

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 32 m/s.

Acceleration (a) = – 1.5 m/s²

Time (t) = 10.8 s.

Final velocity (v) =?

Acceleration is simply defined as the rate of change of velocity with time. Mathematically, it is expressed as:

Acceleration (a) = [final velocity (v) – initial velocity (u)] / time (t)

a = (v – u) /t

With the above formula, we can obtain the final velocity of go-cart driver as follow:

Initial velocity (u) = 32 m/s.

Acceleration (a) = – 1.5 m/s²

Time (t) = 10.8 s.

Final velocity (v) =?

a = (v – u) /t

– 1.5 = (v – 32) / 10.8

Cross multiply

(v – 32) = –1.5 × 10.8

v – 32 = – 16.2

Collect like terms

v = – 16.2 + 32

v = 15.8 m/s

Therefore, the final velocity of go-cart driver is 15.8 m/s.

5 0

3 years ago

A cheetah can run at 105 feet per second, but only for 7 seconds, at which time the animal must stop and rest. A fully rested ch

shepuryov [24]

Answer:

5 seconds

Explanation:

The straight line distance between (0, 0) and the antelope's position (x, y) at time t can be found using distance formula:

d² = x² + y²

d² = (-39 + 40t)² + (228 + 30t)²

d² = 1521 - 3120t + 1600t² + 51984 + 13680t + 900t²

d² = 53505 + 10560t + 2500t²

The cheetah can run a total distance of:

105 * 7 = 735

The time t at this distance is:

735² = 53505 + 10560t + 2500t²

540225 = 53505 + 10560t + 2500t²

0 = -486720 + 10560t + 2500t²

0 = -24336 + 528t + 125t²

t = 12, -16.224

t can't be negative, so t = 12.

Therefore, the cheetah can wait 5 seconds before it has to start running.

5 0

4 years ago

Read 2 more answers