<h3><u>Answer;</u></h3>
1st drop; Motor
2nd drop; Electricity
A device that uses electricity and magnetism to create motion is called a <u>motor</u>. In a reverse process, a device that uses motion and magnesium can be used to create <u>electricity</u>.
<h3><u>Explanation</u>;</h3>
- <em><u>Motors are device which use electricity and magnetism to create motion.</u></em> They pass alternating current through opposing pairs of magnets to create a rotating magnetic field which creates a magnetic field in the rotor of a motor, making it to spin around.
- <em><u>Electric motors work in a reverse process by using motion and magnetism to generate electricity. </u></em>When a coil or loops of wire are exposed to a changing magnetic field, an electrical current arises or is induced.
Using F = Ke
F = 39200×(25÷100) = 39200×0.25
F= 9800N
Answer:
200 N
Explanation:
Since Young's modulus for the metal, E = σ/ε where σ = stress = F/A where F = force on metal and A = cross-sectional area, and ε = strain = e/L where e = extension of metal = change in length and L = length of metal wire.
So, E = σ/ε = FL/eA
Now, since at break extension = e.
So making e subject of the formula, we have
e = FL/EA = FL/Eπr² where r = radius of metal wire
Now, when the radius and length are doubled, we have our extension as e' = F'L'/Eπr'² where F' = new force on metal wire, L' = new length = 2L and r' = new radius = 2r
So, e' = F'(2L)/Eπ(2r)²
e' = 2F'L/4Eπr²
e' = F'L/2Eπr²
Since at breakage, both extensions are the same, e = e'
So, FL/Eπr² = F'L/2Eπr²
F = F'/2
F' = 2F
Since F = 100 N,
F' = 2 × 100 N = 200 N
So, If the radius and length of the wire were both doubled then it would break when the tension reached 200 Newtons.
Answer:
96%
Explanation
Let A the total area of the galaxy, is modeled as a disc:
A = πR^2 = π (25 kpc)^2
And let a be the area that astronomers are able to see:
a = πr^2 = π(5 kpc)^2
The percentage that can be seen is equal to 100 times the ratio of the areas, of the galaxy and the "visible" part:
P = 100 a/A = (5/25)^2 = 100/25 = 4%
Therefore, the percentage of the galaxy not included, i.e. not seen is:
(100-4)% = 96%
