Answer:
t=67.7s
Explanation:
From this question we know that:
Vo = 6m/s
a = 1.8 m/s2
D = 1500m
And we also know that:
Replacing the known values:
Solving for t we get 2 possible answers:
t1 = -44.3s and t2 = 67.7s Since negative time represents an instant before the beginning of the movement, t1 is discarded. So, the final answer is:
t = 67.7s
Answer:
18.6012339739 A
Explanation:
= Vacuum permeability = 
L = Length of wire = 55 cm
N = Number of turns = 4000
I = Current
Magnetic field is given by

The current necessary to produce this field is 18.6012339739 A
The concept required to solve this problem is related to thin film interference.
The path length difference between two waves one is reflected from top surface of the film and the bottom surface of the film is equal to twice the thickness of the film:

Where,
Path length difference
t = thickness
At the same time we have that the constructive interference condition for a thin film interference for strongly reflected rays is

Where
Path length difference
wavelength
m = Any integer (order of the equation) which represent the number of repetition of the spectrum
Equation both expression we have

Re-arrange to find the thickness we have

Our values are given as
m = 1
= 597nm
n = 1.38
Replacing,


Therefore the thinnest thickness of the film is 216.3nm