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3 years ago

Complete the sentence.

Physics

2 answers:

Elena L [17]3 years ago

4 0

Answer:

b. alternating current transmitted at high voltages, but usually used at low voltages.

Explanation:

As we know that transformer is used to convert high voltage AC to low voltage or vice versa.

Here this AC voltage is transmitted at high voltage conditions because here power remains constant.

this power is given by

$P = Vi$

now if we increase the voltage then the current will be less due to which the heat loss in transmission line is small

now when we need to supply it to the homes we will have to decrease the voltage by using the transformer again

Hunter-Best [27]3 years ago

3 0

The best and most correct answer among the choices provided by your question is the second option or letter B. Electric current from a generating plant is alternating current transmitted at high voltages, but usually used at low voltages. That's how an electrical power grid works!

I hope my answer has come to your help. Thank you for posting your question here in Brainly.

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Mike walks 200 km in 6 hours.he then walks another 100km in 4 hours .what is his average speed?

kolbaska11 [484]

Average speed is defined as the ratio of total distance covered in total given time

$speed = \frac{distance}{time}$

here we know that total distance that man moved is

$d_1 = 200 km$

$d_2 = 100 km$

so total distance is

$d = d_1 + d_2$

$d = 200 km + 100 km$

$d = 300 km$

now here total time of the motion is

$t_1 = 6 hours$

$t_2 = 4 hours$

total time will be given as

$t = t_1 + t_2$

$t = 6 + 4 = 10 hours$

now by above formula

$v_{avg} = \frac{300}{10}$

$v_{avg} = 30 km/h$

so his average speed is 30 km/h

8 0

3 years ago

The floor of a railroad flatcar is loaded with loose crates having a coefficient of static friction of 0.32 with the floor. If t

coldgirl [10]

Answer:

The shortest braking distance is 35.8 m

Explanation:

To solve this problem we must use Newton's second law applied to the boxes, on the vertical axis we have the norm up and the weight vertically down

On the horizontal axis we fear the force of friction (fr) that opposes the movement and acceleration of the train, write the equation for each axis

Y axis

N- W = 0

N = W = mg

X axis

-Fr = m a

-μ N = m a

-μ mg = ma

a = μ g

a = - 0.32 9.8

a = - 3.14 m/s²

We calculate the distance using the kinematics equations

Vf² = Vo² + 2 a x

x = (Vf² - Vo²) / 2 a

When the train stops the speed is zero (Vf = 0)

Vo = 54 km/h (1000m/1km) (1 h/3600s)= 15 m/s

x = ( 0 - 15²) / 2 (-3.14)

x= 35.8 m

The shortest braking distance is 35.8 m

7 0

2 years ago

Two capacitors, a 15 micro F and a 25 micro F, are connected in parallel to a 60 Hz source. The total capacitive reactance is :_

Stells [14]

Answer:

3980.89 ohms

Explanation:

The capacitive reactance is expressed as;

$X_c = \frac{1}{2 \pi fC}$

f is the frequency

C is the capacitance of the capacitor

Given

f = 60H

C = C1+C2 (parallel connection)

C = 15μF + 25μF

C = 40μF

C = $40 * 10^{-6}F$

Substitute into the formula:

$X_c = \frac{1}{2(3.14)*60*40*10^{-6}}\\X_c = \frac{1}{0.0002512}\\X_c = 3,980.89$

Hence the total capacitive reactance is 3980.89 ohms

5 0

3 years ago

Are the objects described here in static equilibrium, dynamic equilibrium, or not equilibrium at all? Explain.

Alexandra [31]

Let us examine the given situations one at a time.

Case a. A 200-pound barbell is held over your head.
The barbell is in static equilibrium because it is not moving.
Answer: STATIC EQUILIBRIUM

Case b. A girder is being lifted at a constant speed by a crane.
The girder is moving, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM

Case c: A jet plane has reached its cruising speed at an altitude.
The plane is moving at cruising speed, but not accelerating. It is in dynamic equilibrium.
Answer: DYNAMIC EQUILIBRIUM

Case d: A box in the back of a truck doesn't slide as the truck stops.
The box does not slide because the frictional force between the box and the floor of the truck balances out the inertial force. The box is in static equilibrium.
Answer: STATIC EQUILIBRIUM

4 0

2 years ago

Read 2 more answers

A hot drink in a room is at a temperature of 20 C

IRISSAK [1]

Answer: the drink cooled down to the same temperature as the room it was in.

Explanation: due to the change and temperature of the room, it cause the heat particles to exchange, causing it cool

8 0

3 years ago