Answer:
I will specify a value of 0.009T for the alternator’s magnetic field
Explanation:
E_peak = 14 V
d = 10cm = 0.1m, so r = 0.1/2 =0.05m
N = 250 turns
f = 1200rpm = (1200rp/m x 1m/60sec) = 20 revolutions per second
At peak performance, peak voltage is given by the equation;
E_peak = NABω
Let's make the magnetic field B the subject;
B = E_peak/(NAω)
Now we know that ω = 2πf
Thus, ω = 2π x 20 revs/s = 125.664 revs/s.
Let's convert it to the standard unit which is rad/s.
1 rev/s = 6.283 rad/s
Thus, 125.664 revs/s = 125.664 x 6.283 = 789.55 rad/s
Area (A) = πr² = π x 0.05² = 0.007854 m²
Thus, plugging in the relevant values to get;
B = 14/[(250 x 0.007854 x 789.55)] = 0.009T
Explanation:
the third answer is correct
71.5m/s
Answer:
30.4 s
Explanation:
A pilot , with plane accelerated at 4 g starts greying out . In the problem , the acceleration of jet is 4 g
a = 4 x 9.8 = 39.2 m /s²
initial velocity u = 0
Final velocity = 3.60 times speed of sound
= 3.6 x 331 = 1191.6 m /s
v = u + at
Putting the values
1191.6 = 0 + 39.2 t
t = 30.4 s .
<span>assuming the pitch is 100yards long, the player runs 100yards to the other goal then a further 50 yards back to the 50-yard line. So he/she runs 150yards in 18s
150/18 = 8.33yards per second average speed.
Initial velocity = 0, average velocity =8.33
Vav = (Vinitial+Vfinal)/2
Vav = 4.16m/s</span>
Answer: 1.44. You can set centripetal force equal to gravitational force caused by the earth because the grav. force is what causes the satellite to orbit in a circle