Explanation:
Let f is the frequency of an oscillation and T is the period of the oscillation. There exists an inverse relationship between the frequency and the time period of the oscillation. Mathematically, it is given by :

Also, 
So,

The time taken to complete one oscillation is called the period of the oscillation and the number of oscillation is called the frequency if an oscillation.
Answer:
The rate of change of the distance is 14.89.
Explanation:
Given that,
Distance = 145 miles
Speed of car = 42 miles/hr
Distance covered by car = 55 miles
We need to calculate the the rate of change of the distance
According to figure,
Let OA is x, and AB is y.
Now, using Pythagorean theorem

On differentiating




Hence, The rate of change of the distance is 14.89.
An atomic nucleus . . .
-- contains all of the atom's positive charge
-- contains almost all of the atom's mass
-- contains none of the atom's negative charge.
<h2>
Answer:</h2>
0.31425 Tesla
<h2>
Explanation:</h2>
The magnetic field strength of a solenoid can be found by using the Ampere's law as follows;
BL = μ₀ x N x I -------------------(i)
Where;
B = magnetic field strength
L = length of the solenoid
μ₀ = magnetic constant = 1.257 x 10⁻⁶H/m
N = number of turns in the coil of the solenoid
I = current flowing through the coil of the solenoid.
<em>From the question, </em>
L = 20cm = 0.2m
N = 5000 turns
I = 10A
<em>Substitute these values into equation (i) as follows;</em>
B x 0.2 = 1.257 x 10⁻⁶ x 5000 x 10
0.2B = 6.285 x 10⁻²
<em>Solve for B;</em>
B = 6.285 x 10⁻² / 0.2
B = 31.425 x 10⁻²
B = 0.31425 T
Therefore, the magnetic field strength is 0.31425 Tesla