Answer:
v = 2.85 m/s
Explanation:
By the law of similarity of the triangle we can say
here we know that
height of man = 2 m
let the distance of man from spotlight = x
distance of wall from spotlight = 12 m
height of image is let say "y"
so we will have
now we have
here we know
x = 4 m
now we have
Answer:
35.7 mA
Explanation:
The magnetic field inside a solenoid is given by:
(1)
where
is the vacuum permeability
I is the current
n is the number of turns per unit length
Since we have
N = 870 turns
L = 0.390 (length of the solenoid)
we can calculate n
And now we can re-arrange eq.(1) to find the current, I: