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.
Answer:
60,000 J
Explanation:
The total Energy in the system = the sum of potential and kinetic energy
Total energy = K. E + P. E
K. E = 0.5mv²
m = mass ; v = velocity, K. E = kinetic energy
V = 20 m/s ; mass = 600kg
Total energy = 180000 J
Hence,
K. E = 0.5 * 600 * 20^2
K.E = 300 * 400
K. E = 120,000
P. E = TOTAL ENERGY - K.E
P.E = I80,000 - 120,000
P.E = 60,000 J
Insurance would be a example of benefits because you don’t receive insurance like you would salary, salary is a base thing you receive when you get a job while insurance you only get as a benefit with certain jobs
Answer:
Explanation:
Assume that the bullet is shot at a velocity of (v m/s) and it will take t time to pass the second plate.
by the definition of then angular velocity (ω)
ω=\frac{angular displacement}{time }[/tex]
Lets find the time to turn the next plate by 12 degrees , using θ=ωt
]t=\frac{12}{8995.5} =1.334*10^{-3}[/tex]
the bullet has to travel 80cm in this much of time to make a hole in the second plate. We can find the speed using this equation
(we have to convert cm into meters first)
To solve this problem it is necessary to apply the concepts related to intensity as a function of power and area.
Intensity is defined to be the power per unit area carried by a wave. Power is the rate at which energy is transferred by the wave. In equation form, intensity I is
The area of a sphere is given by
So replacing we have to
Since the question tells us to find the proportion when
So considering the two intensities we have to
The ratio between the two intensities would be
The power does not change therefore it remains constant, which allows summarizing the expression to
Re-arrange to find
Therefore the intensity at five times this distance from the source is