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aleksandrvk [35]
4 years ago
6

5) Old-style dimmers consisted of a variable resistor so you could dial in more resistance to lower the current and, hence, dim

the light. If the increased total resistance caused the current to be reduced by 50%, then by what percent would the power dissipation be reduced
Physics
1 answer:
NeX [460]4 years ago
4 0

Answer:

The power of the bulb is reduced to a quarter

Explanation:

The power in an electrical circuit is

         P = V I = I² R

If the dimmer cuts the current in half

        I = I₀ / 2

The resistance of the light bulb after hot is little affected by small changes in the current

We substitute in the equation

       P = I₂ R

       P = (I₀ /2)² R

      P = ¼ I₀² R

      P = ¼ P₀

The power of the bulb is reduced to a quarter

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Evelynn is measuring the pitch of a piano note. What unit of measurement is she most likely recording her value
sweet [91]

Answer:

hertz

Explanation: play piano

5 0
2 years ago
The radius of a sphere is 2.00 m. What’s the surface area
Svet_ta [14]

S.A of sphere = 4πr²

r = 2m

S.A = 4π *4

S.A = 50.26m²

5 0
3 years ago
A swimmer travels from the south end to the north end of a 30.0 m pool in 15.0 s and makes the return trip to the starting posit
JulsSmile [24]

Answer:

Zero

Explanation:

Average velocity is given by:

v=\frac{d}{t}

where

d is the displacement of the trip

t is the time it takes for the trip to complete

In this problem, the net displacement of the swimmer is zero. In fact:

- First, he swims 30.0 m in the north direction

- Then, he travels back (-30.0 m) in the south direction, to the starting position

Since the final position is equal to the starting position, the displacement is zero:

d = 0

And therefore, the average velocity is also zero.

8 0
4 years ago
While standing at the top of an 100 m high observatory, you accidentally dropped your phone through the grates (it is now fallin
Arturiano [62]

Using the idea of motion under gravity, it will take 0.5 seconds more before the phone hits the ground.

<h3>What is the distance covered?</h3>

The distance covered is obtained form the equations of kinematics under gravity.

Now;

v = u + gt

Recall that it was dropped from a height hence u = 0 m/s

v = gt

v = 9.8 m/s^2 * 4 s

v = 39.2 m/s

Now;

h = ut + 1/2gt^2

but u = 0 m/s

h = 1/2gt^2

h = 1/2 * 9.8 * (4)^2

h = 78.4 m

The phone  will not hit the ground within this time

For the phone to hit the ground;

h = 1/2gt^2

if h = 100 m

100 = 1/2 * 9.8 * t^2

2 * 100/9.8 =  t^2

t = √2 * 100/9.8

t = 4.5 seconds

It will take about 0.5 seconds more before the phone will hit the ground.

Learn more about motion under gravity:brainly.com/question/15120445

#SPJ1

3 0
2 years ago
The force produced by gravity on a mass is called
Yakvenalex [24]

Answer:

gravitational force

weight

Explanation:

5 0
4 years ago
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