Three science questions help please!
1 answer:
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Answer:
induced EMF = 240 V
and by the lenz's law direction of induced EMF is opposite to the applied EMF
Explanation:
given data
inductance = 8 mH
resistance = 5 Ω
current = 4.0 A
time t = 0
current grow = 4.0 A to 10.0 A
to find out
value and the direction of the induced EMF
solution
we get here induced EMF of induction is express as
E = - L ...................1
so E = - L
put here value we get
E = - 8 ×
E = -40 × 6
E = -240
take magnitude
induced EMF = 240 V
and by the lenz's law we get direction of induced EMF is opposite to the applied EMF
Answer:
V1 =8.1 m/s
Explanation:
height at highest point (h2) = 4.1 m
height at lowest point (h1) = 0.8 m
acceleration due to gravity (g) = 9.8 m/s^{2}
from conservation of energy, the total energy at the lowest point will be the same as the total energy at the highest point. therefore
mgh1 + = mgh2 +
where
- speed at highest point = V2
- speed at lowest point = V1
- mass of the girl and swing = m
- at the highest point, the speed is minimum (V1 = 0)
- at the lowest point the speed is maximum (V2 is the maximum speed)
- therefore the equation becomes mgh1 +
= mgh2
m(gh1 + ) = m(gh2)
gh1 + = gh2
V1 =
now we can substitute all required values into the equation above.
V1 =
V1 =
V1 =8.1 m/s