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3 years ago

6

Write an expression for the instantaneous voltage V ( t ) delivered by an ac generator supplying 130 V rms at 65 Hz . Assume the

voltage is 0 at time t = 0 , and leave the factors in exact form; do not round their values. Write the argument of the sinusoidal function to have units of radians, but omit the units.

1 answer:

Svetllana [295]3 years ago

4 0

Answer:

$V(t)=130\sqrt{2}\sin(130\pi t)V$

Explanation:

$V_r$ = RMS voltage = 130 V

f = Frequency = 65 Hz

Instantaneous voltage is given by

$V=\sqrt{2}V_r\sin(2\pi ft+\phi)$

$\\\Rightarrow V(t)=130\sqrt{2}\sin(2\pi 65t+\phi)\\\Rightarrow V(t)=130\sqrt{2}\sin(130\pi t+\phi)$

at t = 0 v = 0

$V(0)=130\sqrt{2}\sin(130\pi \times 0+\phi)\\\Rightarrow 0=130\sqrt{2}\sin(130\pi \times 0+\phi)\\\Rightarrow sin\phi=0\\\Rightarrow \phi=0$

So, the function is

$V(t)=130\sqrt{2}\sin(130\pi t)V$

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Answer:

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4 years ago

Commercially-available hybrid vehicles, such as the Toyota Prius, use electrical batteries to store energy for later use. Howeve

Bad White [126]

(A) $4.2\cdot 10^5 J$

The energy stored by the system is given by

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where

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In this case, we have

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t = 7 is the time

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$E=(60,000 W)(7 s)=4.2\cdot 10^5 J$

(B) 4830 rad/s

The rotational energy of the wheel is given by

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where

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$\omega$ is the angular velocity

The moment of inertia of the wheel is

$I=\frac{1}{2}MR^2=\frac{1}{2}(5 kg)(0.12 m)^2=0.036 kg m^2$

where M is the mass and R the radius of the wheel.

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$E=4.2\cdot 10^5 J$

So we can rearrange eq.(1) to find the angular velocity:

$\omega=\sqrt{\frac{2E}{I}}=\sqrt{\frac{2(4.2\cdot 10^5 J)}{0.036 kg m^2}}=4830 rad/s$

(C) $2.8\cdot 10^6 m/s^2$

The centripetal acceleration of a point on the edge is given by

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where

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4 years ago

Question 2 Ammonium phosphate NH43PO4 is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid

Mama L [17]

Answer:

The answer is 12.27 g (NH4)3PO4

Explanation:

Step 1: balance the chemical equation:

H3PO4 + 3NH3 → (NH4)3PO4

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3 atoms of H: 3x1=3 g/mol

1 atom of P: 1x30.97=30.97 g/mol

4 atoms of O: 4x16=64 g/mol

Molar mass=3+30.97+64=97.97 g/mol

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3 atoms of N: 3x14=42 g/mol

9 atoms of H: 9x1=9 g/mol

Molar mass=42+9=51 g/mol

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3 atoms of N: 3x14=42 g/mol

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4 atoms of O: 4x16=64 g/mol

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we make a rule of three to calculate the amount of ammonium phosphate:

51 g NH3------------------148.97 g (NH4)3PO4

4.2 g NH3-----------------x g (NH4)3PO4

Clearing the x, we have:

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4 years ago

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Answer:

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Explanation:

As we know that the magnetic field near the center of the solenoid is given as

$B = \mu_0 ni$

Also we know by equation of Faraday's law

EMF induced in the closed loop will be equal to rate of change in magnetic flux

so we have

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so we have

$\int E. dL = \pi r^2 (\mu_0 n \frac{di}{dt})$

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Part a)

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Part b)

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3 years ago

A steel beam that is 6.50 m long weighs 336 N. It rests on two supports, 3.00 m apart, with equal amounts of the beam extending

FinnZ [79.3K]

Answer:

Explanation:

When beam is balanced and not rotating with Suki standing on it , let reaction force on the supports be R₁ and R₂. Then

R₁ +R₂ = 336 + 590

= 929

Now the moment beam begins to tip , reaction on distant support R₁ = 0

only R₂ will exists on the support near to Suki.

Taking torque about this support of weight of beam acting from the middle point and weight of suki of 590N ,who is x distance from the support towards the other end.

336 x 1.5 = 590 x

x = .85 m

ie , from second support , Suki can not go beyond a distance of .85 m towards the second end.

4 0

3 years ago