<span>Strong evidence that the universe is expanding comes from the fact that the light emitted from nearly all distant galaxies appears to be moving away much faster than those that are close by.</span>
Answer:
L = 0.475 m = 475 mm = 18.7 inches
Explanation:
A cylindrical specimen of a nickel alloy having an elastic modulus of 207 GPa and an original diameter of 10.2 mm (0.40 in.) will experience only elastic deformation when a tensile load of 8900 N (2000 lb ) is applied. Compute the maximum length of the specimen before deformation if the maximum allowable elongation is 0.25 mm (0.010 in).
E = 207 GPa = 207*10⁹ Pa
D = 10.2 mm = 0.0102 m
P = 8900 N
ΔL = 0.25 mm = 2.5*10⁻⁴ m
L = ?
We can use the Equation of the Hooke's Law
ΔL = P*L / (A*E) ⇒ L = ΔL*A*E / P
⇒ L = (2.5*10⁻⁴ m)*(π*(0.0102 m)²*0.25)*(207*10⁹ Pa) / (8900 N)
⇒ L = 0.475 m = 475 mm = 18.7 inches
Sometimes, because acceleration due to gravity on Earth depends on how close you are to the Earth's center.
Is there a multiple choice?
The force of friction is equal to the pushing force, and the acceleration is zero
Explanation:
In this problem, we are pushing a piano along the floor, in the horizontal direction.
There are 2 forces acting in the horizontal direction on the piano:
- The applied force,
, acting forward - The force of friction,
, acting backward
Therefore, the net force in the horizontal direction is
According to Newton's second law, the net force is equal to the product between the piano's mass (m) and its acceleration:
Combining the two equations,
However, we are also told that the piano moves at constant speed, therefore the acceleration is zero:
And so,
which means that the force of friction is equal to the applied force.
Learn more about Newton's second law:
brainly.com/question/3820012
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