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mario62 [17]
3 years ago
7

Need help with these 4 questions

Physics
1 answer:
dimaraw [331]3 years ago
4 0

Answer: 1. B

2.A

3.B

4. A

Explanation:

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A charge of 12 passes through the filament of a car head lamp bulb in 4 s. what is current?​
Katena32 [7]

Answer:

3 A

Explanation:

current =  \frac{charge}{time}  \\  =  \frac{12}{4}  \\  = 3 \: amperes

3 0
3 years ago
A motor has an armature resistance of 3.75 Ω . Part A If it draws 9.10 A when running at full speed and connected to a 120-V lin
bulgar [2K]

Back emf is 85.9 V.

<u>Explanation:</u>

Given-

Resistance, R = 3.75Ω

Current, I = 9.1 A

Supply Voltage, V = 120 V

Back emf = ?

Assumption - There is no effects of inductance.

A motor will have a back emf that opposes the supply voltage, as the motor speeds up the back emf increases and has the effect that the difference between the supply voltage and the back emf is what causes the current to flow through the armature resistance.

So if 9.1 A flows through the resistance of 3.75Ω then by Ohms law,

The voltage across the resistance would be

v = I x R

  = 9.1 x 3.75

  = 34.125 volts

We know,

supply voltage = back emf + voltage across the resistance

By plugging in the values,

120 V = back emf + 34.125 V

Back emf = 120 - 34.125

                = 85.9 Volts

Therefore, back emf is 85.9 V.

4 0
3 years ago
A ball is thrown straight up with an initial speed of 12 m/s. What are the velocity and acceleration when it is at the top of it
Lesechka [4]

Answer:

'A ball is thrown straight up with an initial speed of 12 m/s_ What are the velocity and acceleration when it is at the top of its trajectory? Select all apply. v=12 mls a = 0 v =-12 mls a = 9.8 m/s2 Oa=-9.8 m/s2'

Explanation:

I look it up

Hope this helps

8 0
2 years ago
State whether a speedometer reading of 45 km/h is the average or instantaneous speed of the car
kompoz [17]
Thats is instantaneous bc it’s in the moment
5 0
2 years ago
What type of force keeps the Earth in orbit around the Sun?
olchik [2.2K]
That would be the one written about by Newton - Gravity
7 0
3 years ago
Read 2 more answers
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