Answer:
6.03 mV
Explanation:
length of solenoid, L = 2 m, N = 12000, di/dt = 40 A/s,
Magnetic field due to solenoid
B = μ0 n i = μ0 N i / L
dB/dt = μ0 N / L x di / dt
dB /dt = (4 x 3.14 x 10^-7 x 12000 x 40) / 2 = 0.3 T/s
Induced emf, e = rate of change of magnetic flux
e = dΦ / dt = A x dB / dt
e = 3.14 x 0.08 x 0.08 x 0.3 = 6.03 x 10^-3 V = 6.03 mV
Answer:
The average speed of the elevator going down in the abandoned mine is 17.722mph.
Explanation:
If the elevator takes 90 seconds to descend a height of 713m, the average speed of the elevator is:

And if 1m/s is 2.23694mph, the average speed is:
.
Acceleration is a derived unit because it is derived from two quantities : Velocity and time.
We know, acceleration = Change in velocity/Time
S = d/t, s = 120, d = 2000, t = ?
Input the values,
120 = 2000/t
Make t the subject of the formula by cross multiplying, Therefore,
120t = 2000
Divide both sides by 120
t = 16.7hrs to 1 decimal place.
If you're asked to convert it, you can.
The answer is 2Hz
Using the formula f= 1/T we can plug in .5 for T and solve for frequency.