Answer:
Least to most elongated: tungsten, copper, aluminum, nylon.
Explanation:
Materials with high Young's modulus are difficult to stretch. σ = Yε and ε = ΔL/L so an object with a high Young's modulus (Y) subject to a certain tensile stress (σ) will have a smaller strain than an object with a smaller Young's 's modulus subject to the same tensile stress. If strain (ε) is smaller, then ΔL will also be smaller.
Answer:
a)W= - 47.19 J
b)47.19 J
Explanation:
Given that
Weight ,mg= 71.5 N
y= 1.84 m
H= 2.5
a)
The distance above the hand ,h= 2.5 - 1.84 m
h= 0.66 m
We know that gravitaional force act in the downward direction but the displacement is in upward direction that is why work done will be negative.
W= - m g h
W= -71.5 x 0.66 J
W= - 47.19 J
b)
The potential energy at initial position = m g y
The potential energy at final position = m g H
So change in the potential energy = m g H - m g y
= mg ( H- y)
=71.5 ( 2.5 - 1.84 ) = 47.19 J
Therefore change in the potential energy = 47.19 J
Total internal refraction occurs when a ray of light meets the following conditions.
1. light falls from an optically dense material to a less dense material.
2. The angle of incident in the denser media must be greater than the critical angle.
In the case above the fiber-optic is optically denser than water. Since the light is incident to fiber-optic-water interface, then one condition is fulfilled.
Checking the other condition we carry out the calculation below;
n1sinФ1=n2sinФ2
where c ⇒critical angle
1.53 sinc = 1.33 sin 90
sinc =0.86928
c = 60.37°
The angle of incident is (65°-70°) is greater than critical angle.
With certainty, there would be no refraction. Total internal reflection would occur.
Using Placks’s constant and frequency
