All categories

3 years ago

How does an electric motor use magnetic force to produce motion?

Physics

2 answers:

DerKrebs [107]3 years ago

8 0

Answer:

The north pole of an electromagnet placed in the center of a permanent magnet repels the north pole of the permanent magnet.

Explanation:

The commutator of the electric motor reverses the current in each half revolution to keep the torque, turning the coil in the same direction. This occurs as the north pole of the electromagnet nears the south pole of the permanent magnet, and the current reverses, which causes the poles of the magnets to repel.

Thus, the correct answer is "the north pole of an electromagnet placed in the center of a permanent magnet repels the north pole of the permanent magnet".

Lerok [7]3 years ago

8 0

Answer:

The answer is D

Explanation:

Just took the test on Edge :)

You might be interested in

What kind of stars make up the halo?

Step2247 [10]

By definition, a halo is a part of a galaxy wherein it mainly consists of scattered stars forming bulges having a significantly spherical structure. In addition, the galactic structure is commonly made up of old and metal-rich stars forming clouds of gas and dirt at the spirals of a galaxy.

8 0

4 years ago

Read 2 more answers

Which of the following are examples of chemical energy being released or stored?

damaskus [11]

I is the right answer if

3 0

3 years ago

Read 2 more answers

The 3670-lb car is traveling at 25 mi/hr when the driver applies the brakes, and the car continues to move along the circular pa

Monica [59]

Answer:

$a_t = -14.37407175$

Explanation:

I was unable to submit this answer after typing it, so i create a document file that clearly shows and depicts all explanations for the question. OR

You can check the three picture slides i attached as well for the explanation.

The attached file for the document and the picture can be found below.

Download docx

5 0

3 years ago

1) Find the voltage on a circuit with a resistance of 12.5 Ω if it has a current of 2.35 A.

KengaRu [80]

1. The voltage on the circuit with a resistance of 12.5 Ω and current of 2.35 A is 29.4 V.

2.The resistance in the circuit is found to be 1.45 Ω.

3. The equivalent resistance of the resistors connected in series is 24 Ω.

4. The equivalent resistance of the resistors connected in parallel is 2.18Ω.

5. The power generated is 552.5 W.

6. The frequency of the green light is 0.56×10¹⁵ Hz.

Explanation:

1) This problem can be solved using Ohm's law. Here the resistance (R) of the circuit is given to be 12.5 Ω and the current (I) is stated to be 2.35 A. So the ohm's law states that in a closed circuit, the voltage will be directly proportional to the current flowing in the circuit and the resistance will act as the proportionality constant.

$V = I * R = 2.35*12.5 = 29.4 V$

So, the voltage on the circuit with a resistance of 12.5 Ω and current of 2.35 A is 29.4 V.

2) Using the same Ohms' law, now we have to determine the resistance. So in this case, the voltage is given as 9 V and the current is said to be 6.2 A, then resistance can be determined as the ratio of voltage to current.

$R = \frac{V}{I} =\frac{9}{6.2} =1.45 Ohms$

So, the resistance in the circuit is found to be 1.45 Ω.

3) Here, the resistances of three resistors are given as 4 Ω, 8 Ω and 12 Ω. And it is stated that the resistances are connected or wired in series. Then the equivalent resistance will be obtained by the sum of resistances of three resistors, as the current flow will be constant in all the three resistors.

$R_{s} = R_{1} + R_{2} + R_{3} \\ \\R_{s} = 4+8+12 = 24 ohms$

Thus, the equivalent resistance of the resistors connected in series is 24 Ω.

4) Now, if the resistors are connected in parallel, then the equivalent resistance will be ratio of product of resistances to the sum of the resistances.

$\frac{1}{R_{p} }= \frac{1}{R_{1} } + \frac{1}{R_{2} } +\frac{1}{R_{3} }\\\\\frac{1}{R_{p} }=\frac{1}{4}+ \frac{1}{8} +\frac{1}{12} = \frac{6+3+2}{24} =\frac{11}{24} \\\\R_{p} = \frac{24}{11 } =2.18 Ohm$

Thus, the equivalent resistance of the resistors connected in parallel is 2.18Ω.

5) Power generated by the person can be obtained by the ratio of work done by the person to the time in which the work is done. So the work done can be obtained by the product of force with displacement.

As here the weight lifted by the person will act as dominant force on the person. So the force is considered as F = 956 N and the displacement is d = 2.41 m, then

$Work done = Force * displacement = 956*2.41 =2303.96 J$

So, the work done is obtained as 2303.96 J and the time is given as 4.17 s, then

$Power = \frac{Work done}{Time} =\frac{2303.96}{4.17} =552.5 W$

So, the power generated is 552.5 W.

6) In this, the wavelength of green light is given as 5.34 × 10⁻⁷ m. It is known that the wavelength is inversely proportional to the frequency.

$Wavelength = \frac{Speed of light}{Frequency}$

As, speed of light is known as 3×10⁸ m/s, the frequency will be determined as the ratio of speed of light to wavelength.

$Frequency = \frac{Speed of light}{Wavelength} =\frac{3*10^{8} }{5.34*10^{-7} } \\\\Frequency =0.56*10^{15} Hz$

Thus, the frequency of the green light is 0.56×10¹⁵ Hz.

8 0

4 years ago

Why does the percentage of water vapor vary?

Mademuasel [1]

Because temperature sets a limit to how much water vapor can be in the air.

7 0

3 years ago