Answer:
33.48 V
Explanation:
Parameters given:
Number of turns, N = 420
Magnetic field strength, B = 0.055 T
Area, A = 0.065 m²
Angular velocity, ω = 22.3 rad/s
EMF induced in a coil is given as:
EMF = -dΦ/dt
where Φ = magnetic flux
Magnetic flux, Φ, is given as:
Φ = B * N * A * cosωt
EMF = -d( B * N * A * cosωt) / dt
EMF = B * N * A * ω * sinωt
where ωt = 90°
Therefore:
EMF = 0.055 * 420 * 0.065 * 22.3 * sin90°
EMF = 33.48 V
D, it is considered unethical today
Answer:
F = 4000 N
Explanation:
given,
mass of rocket (M)= 5000 Kg
10 Kg gas burns at speed (m)= 4000 m/s
time = 10 s
average force = ?
at the end the rocket is at rest
by conservation of momentum
M v + m v' = 0
5000 x v - 10 x 4000 = 0
5000 v = 40000
v = 8 m/s
speed of rocket = 8 m/s
now,
we know
change in momentum = F x Δ t
F = 4000 N
Hence, the average force applied to the rocket is equal to F = 4000 N
f' = frequency observed by the police car after sound reflected from the vehicle and comes back to police car = 1250 Hz
f = frequency emitted by the police car = 1200 Hz
V = speed of sound = 340 m/s
v = speed of vehicle = ?
frequency observed by the police car is given as
f' = f (V + v)/(V - v)
inserting the values in the above equation
1250 = 1200 (340 + v)/(340 - v)
v = 6.9 m/s
