The Second Law of Thermodynamics states that the state of entropy of the entire universe, as an isolated system, will always increase over time.
Take that as you will
Answer:
V_{a} - V_{b} = 89.3
Explanation:
The electric potential is defined by
= - ∫ E .ds
In this case the electric field is in the direction and the points (ds) are also in the direction and therefore the angle is zero and the scalar product is reduced to the algebraic product.
V_{b} - V_{a} = - ∫ E ds
We substitute
V_{b} - V_{a} = - ∫ (α + β/ y²) dy
We integrate
V_{b} - V_{a} = - α y + β / y
We evaluate between the lower limit A 2 cm = 0.02 m and the upper limit B 3 cm = 0.03 m
V_{b} - V_{a} = - α (0.03 - 0.02) + β (1 / 0.03 - 1 / 0.02)
V_{b} - V_{a} = - 600 0.01 + 5 (-16.67) = -6 - 83.33
V_{b} - V_{a} = - 89.3 V
As they ask us the reverse case
V_{b} - V_{a} = - V_{b} - V_{a}
V_{a} - V_{b} = 89.3
Weight, w = mg. g ≈ 9.8 m/s². m = mass in kg. w is weight in N
441 N = m* 9.8
9.8m = 441
m = 441/9.8
m = 45 kg.
Mass of the dog is = 45 kg
I made the drawing in the attached file.
I included two figures.
The upper figure shows the effect of:
- multiplying vector A times 1.5.
It is drawn in red with dotted line.
- multiplying vector B times - 3 .
It is drawn in purple with dotted line.
In the lower figure you have the resultant vector: C = 1.5A - 3B.
The method is that you translate the tail of the vector -3B unitl the point of the vector 1,5A, preserving the angles.
Then you draw the arrow that joins the tail of 1,5A with the point of -3B after translation.
The resultant arrow is the vector C and it is drawn in black dotted line.
let the length of the beam be "L"
from the diagram
AD = length of beam = L
AC = CD = AD/2 = L/2
BC = AC - AB = (L/2) - 1.10
BD = AD - AB = L - 1.10
m = mass of beam = 20 kg
m₁ = mass of child on left end = 30 kg
m₂ = mass of child on right end = 40 kg
using equilibrium of torque about B
(m₁ g) (AB) = (mg) (BC) + (m₂ g) (BD)
30 (1.10) = (20) ((L/2) - 1.10) + (40) (L - 1.10)
L = 1.98 m