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2 years ago

6. The peak value of an AC sine wave is

Physics

1 answer:

Sonbull [250]2 years ago

3 0

Answer:

B. 85 V

Explanation:

E(rms) = E(peak-to-peak) / squareroot(2)

E(rms) = 120V / 1.414 = 84.9 V

(When rounded) = 85 V

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The volume of water in a measuring cylinder is 50 ml. When a piece of stone is immersed

Sergio039 [100]

Volume = 873 - 50 = 723 cm^3

4 0

2 years ago

Describe the sequence of mechanical energy events that lets you hear the

lina2011 [118]

Answer:

Starting from the beginning.

There is a radio signal that is received by the radio.

The radio interprets the signal and produces a current in response to it.

That current goes to a membrane that oscillates producing sound, the oscillation of the membrane is the first mechanical energy event here.

These oscillations can travel in material mediums, for example, the air. Then there is a production of waves (soundwaves) that travel in the air (second event).

Those waves now hit the wall that separates you and your neighbor, as the wall is made of a material, the soundwaves can travel through it, but they will be dispersed (a part of the waves rebounds on the wall, and another part is dissipated as the wave travels through the wall), there is also a transmitted part of the wave, that is now in your house. (this change of medium will be the third event). Now only the lower frequencies survive, this is why the sound is "muffled".

Those remaining frequencies now travel in your house, and when they reach your ear, your ear sends a signal to your brain and your brain interprets them as sound. The wave interacting with your ear will be the fourth and last mechanical energy event.

3 0

2 years ago

A bicyclist bikes the 90 mi to a city averaging a certain speed. The return trip is made at a speed that is 1 mph slower. Total

Lynna [10]

Answer:

his speeds while going to city is 10 mph and while his round trip the speed will be 9 mph

Explanation:

Let say the speed of the bicycle while he moves towards the city is "v"

now the speed of the round trip must be smaller by 1 mph

so its speed for round trip will be

$v_2 = v - 1$

now we know that total time of the motion is 19 hr

so we will have

$t_1 = \frac{90}{v}$

$t_2 = \frac{90}{v - 1}$

so we will have

$t_1 + t_2 = 19 hr$

$\frac{90}{v} + \frac{90}{v-1} = 19$

$90(2v - 1) = 19(v^2 - v)$

$19 v^2 - 199 v + 90 = 0$

by solving above equation we have

$v = 10 mph$

so his speeds while going to city is 10 mph and while his round trip the speed will be 9 mph

5 0

2 years ago

12. A frain moves from rest to a speed of 25 m/s in 30.0 seconds. What is its acceleration?

ziro4ka [17]

initial velocity=u=0m/s
Final velocity=v=25m/s
Time=t=30s

$\\ \tt\longmapsto Acceleration=\dfrac{v-u}{t}$

$\\ \tt\longmapsto Acceleration=\dfrac{25-0}{30}$

$\\ \tt\longmapsto Acceleration=\dfrac{25}{30}$

$\\ \tt\longmapsto Acceleration=0.8m/s^2$

6 0

2 years ago

A motorist is driving at 20m/s when she sees that a traffic light 200m ahead has just turned red. She knows that this light stay

yuradex [85]

Answer:

5.71428571422 m/s

Explanation:

u = Initial velocity = 20 m/s

v = Final velocity

s = Displacement

a = Acceleration

Time taken = 15-1 = 14 s

Distance traveled in 1 second = $20\times 1=20\ m$

$s=ut+\frac{1}{2}at^2\\\Rightarrow 200-20=20\times 14+\frac{1}{2}\times a\times 14^2\\\Rightarrow a=\frac{2(180-20\times14)}{14^2}\\\Rightarrow a=-1.02040816327\ m/s^2$

$v=u+at\\\Rightarrow v=20-1.02040816327\times 14\\\Rightarrow v=5.71428571422\ m/s$

The speed as she reaches the light at the instant it turns green is 5.71428571422 m/s

4 0

3 years ago