Answer:
The distance of stars and the earth can be averagely measured by using the knowledge of geometry to estimate the stellar parallax angle(p).
From the equation below, the stars distances can be calculated.
D = 1/p
Distance = 1/(parallax angle)
Stellar parallax can be used to determine the distance of stars from an observer, on the surface of the earth due to the motion of the observer. It is the relative or apparent angular displacement of the star, due to the displacement of the observer.
Explanation:
Parallax is the observed apparent change in the position of an object resulting from a change in the position of the observer. Specifically, in the case of astronomy it refers to the apparent displacement of a nearby star as seen from an observer on Earth.
The parallax of an object can be used to approximate the distance to an object using the formula:
D = 1/p
Where p is the parallax angle observed using geometry and D is the actual distance measured in parsecs. A parsec is defined as the distance at which an object has a parallax of 1 arcsecond. This distance is approximately 3.26 light years
Answer:
When the velocity doesn't change its direction
Explanation:
Since velocity vector has 2 components: direction and magnitude, and speed is the velocity's magnitude. So if the velocity doesn't change its direction, we essentially use its magnitude, aka speed, to calculate the rate of change for acceleration.
<h3>Answer</h3>
(A) Resistance is directly related to length.
<h3>Explanation</h3>
Formula for resistance
R = p(length) / A
where R = resistance
p = resistivity(material of wire)
A = cross sectional area
So it can be seen that resistance depends upon 3 factors that are length of wire , resistivity of wire and the cross sectional area of the wire.
If two of the factors, resistivity and cross sectional area, are kept constant then the resistance is directly proportional to the length of wire.
<h3> R ∝ length</h3>
This means that the resistance of the wire increases with the increase in length of the wire and decreases with the decrease of length of the wire.
B. Because they are used to see through objects
