When developing a question for a scientific inquiry, the question will ideally :
- be measurable
- Will have various variables that could be used for further testing
- not just simply ask why
hope this helps
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.
The blue car is moving with a velocity of -14 m/s using the red car as a reference frame.
I had a teat and the answer was A
Total distance is 28+12+34=74km=74000m.
Total time is 20+8+25 minutes=53 minutes=53×60=3180 secs.
Average speed is 74000/3180=23.27 m/s.