Answer:
<h2>
d₂ = 3d</h2><h2>
The diameter of the second wire is 3 times that of the initial wire.</h2>
Explanation:
Using the formula for calculating the resistivity of an object to find the diameter.
Resistivity P = RA/L
R is the resistance of the material
A is the cross sectional area
L is the length of the material
Since A = πd²/4
P = R( πd²/4)/L
P = Rπd²/4L ... 1
If the second wire of the same material and length is found to have resistance R/9, the resistivity of the second material will be;
P₂ = (R/9)A₂/L₂
P₂ = (R/9)(πd₂²/4)/L₂
P₂ = (Rπd₂²/36)/L₂
P₂ = (Rπd₂²)/36L₂
Since the length and resistivity are the same;
P = P₂ and L =L₂
Equating 1 and 2;
Rπd²/4L = (Rπd₂²)/36L₂
Rπd²/4L = (Rπd₂²)/36L
d² = d₂²/9
d₂² = 9d²
Taking the square root of both sides;
√d₂² = √9d²
d₂ = 3d
Therefore the diameter of the second wire is 3 times that of the initial wire
Answer:
An example of kinetic energy is a <u><em>car coming to a stop</em></u>
Explanation:
Kinetic energy is the energy that a body or system possesses due to its movement. In physics this energy is defined as the amount of work necessary to accelerate a body of a certain mass and in rest position, until reaching a certain speed. This energy obtained will remain unchanged as long as this body does not vary its speed. That is, kinetic energy measures how many changes an object that is moving can cause.
<u><em>An example of kinetic energy is a car coming to a stop</em></u>. If the car is moving and comes to a stop, there is a change in speed, therefore in movement, eventually producing a change in kinetic energy. This energy depends on the mass of the body, in this case the car, and the speed. As the speed decreases, the kinetic energy will decrease.
The phrase "light year" is a <u><em>distance</em></u> ... it's the distance that light travels through vacuum in one year.
When you look at an object located 1 light year away from you, you see it as it was 1 year ago.
If a star located 10 light years away from us suddenly brightens, or dims, or explodes, we see the event <em>10 years later.</em>
