Answer: The crust of the Earth has some permanent magnetization, and the Earth's core generates its own magnetic field, sustaining the main part of the field we measure at the surface. So we could say that the Earth is, therefore, a "magnet."
Explanation:
Answer:
The age of the universe would be 9.9 billion years
Explanation:
We can calculate an estimate for the age of the Universe from Hubble's Law. Let's suppose the distance between two galaxies is D and the apparent velocity with which they are separating from each other is v. At some point, the galaxies were touching, and we can consider that time the moment of the Big Bang.
Thus, the time it has taken for the galaxies to reach their current separations is:
and from Hubble's Law:
Therefore:
With the given value for the Hubble's constant we have:
and thus,
Given Information:
Force = f = 1 pound
Stretched length = x = 0.1 ft
Required Information:
Work done = W = ?
Answer:
Work done = 6.05 ft.lb
Explanation:
From the Hook's law we know that
f(x) = kx
Where f is the applied force, k is spring constant and x is length of spring being stretched.
k = F/x
k = 1/0.1
k = 10 lb/ft
f(x) = 10x
The work done is given by
W = ∫ f(x) dx
Where f(x) = 10x and limits of integration are (1.1, 0)
W = ∫ 10x dx
W = 10*x²/2
W = 5x²
Evaluating the limits,
W = 5(1.1)² - 5(0)²
W = 6.05 - 0
W = 6.05 ft.lb
Therefore, 6.05 ft.lb work has been done in stretching the spring from its natural length to 1.1 feet beyond it's natural length.