See for yourself how the forces of electricity and magnetism can work together by building a simple DC electric motor using simple materials you can find in any hardware store!
Electricity and magnetism are both forces caused by the movement of tiny charged particles that make up atoms, the building blocks of all matter. When a wire is hooked up to a battery, current flows through the wire because negatively charged electrons flow from the negative terminal of the battery toward the positive terminal of the battery because opposite charges attract each other, while similar charges repel each other. This flow of electrons through the wire is an electric current, and it produces a magnetic field.
In a magnet, atoms are lined up so that the negatively charged electrons are all spinning in the same direction. Like an electric current, the movement of the electrons creates a magnetic force. The area around the magnet where the force is active is called a magnetic field. Metal objects and other magnets that enter this field will be pulled toward the magnet.
The way the atoms are lined up creates two different poles in the magnet, a north pole and a south pole. As with electrical charges, opposite poles attract each other, while like poles repel each other.
Learn about electromagnetism and its many uses here.
Now let's watch it work as we build a motor.
(Note: This science project requires adult supervision.)
Answer:
Explanation:
mass, m = 1 kg
Position (2, 3 ) m
height, h = 2 m
acceleration due to gravity, g = 9.8 m/s^2
Here, no force is acting in horizontal direction, the force of gravity is acting in vertical direction, so the work done by the gravitational force is to be calculated.
Force mass x acceleration due to gravity
F = 1 x 9.8 = 9.8 N
Work = force x displacement x CosФ
Where, Ф be the angle between force vector and the displacement vector.
Here the value of Ф is 180° as the force acting vertically downward and the displacement is upward
So, W = 9.8 x 2 x Cos 180°
W = - 19.6 J
Thus, option (A) is correct.
Answer:
The work done shall be 14715 Joules
Explanation:
The work done by a force 'F' in a displacement 'dy' is given by
At any position 'y' the weight shall be sum of weft of water and weight of string
Thus applying values we get
Answer:
Option 3: -48 cm
Explanation:
We are given:
refractive index; n = 1.5
radius of curvature; r2 = 24 cm
Formula for the focal length is given as;
1/f = (n - 1) × [(1/r1) - (1/r2)]
As r1 tends to infinity, 1/r1 = 0
Thus,we now have;
1/f = (n - 1) × (-1/r2)
Plugging in the relevant values;
1/f = (1.5 - 1) × (-1/24)
1/f = -0.02083333333
f = -1/0.02083333333
f = -48 cm
Answer:
ΔE> E_minimo
We see that the field difference between these two flowers is greater than the minimum field, so the bee knows if it has been recently visited, so the answer is if it can detect the difference
Explanation:
For this exercise let's use the electric field expression
E = k q / r²
where k is the Coulomb constant that is equal to 9 109 N m² /C², q the charge and r the distance to the point of interest positive test charge, in this case the distance to the bee
let's calculate the field for each charge
Q = 24 pC = 24 10⁻¹² C
E₁ = 9 10⁹ 24 10⁻¹² / 0.20²
E₁ = 5.4 N / C
Q = 32 pC = 32 10⁻¹² C
E₂ = 9 10⁹ 32 10⁻¹² / 0.2²
E₂ = 7.2 N / C
let's find the difference between these two fields
ΔE = E₂ -E₁
ΔE = 7.2 - 5.4
ΔE = 1.8 N / C
the minimum detection field is
E_minimum = 0.77 N / C
ΔE> E_minimo
We see that the field difference between these two flowers is greater than the minimum field, so the bee knows if it has been recently visited, so the answer is if it can detect the difference
