Khi tia tới hợp với pháp tuyến tại điểm một góc i = 30 độ thì tia phản xạ hợp với pháp tuyến tại điểm tới một góc

Given that the electromagnetic force is far stronger than gravity on a per-particle basis, why doesn't the electromagnetic force

Kaylis [27]

Explanation:

The electro magnetic force is given by

F = $\frac{k.q_{1}.q_{2}}{r^{2}}$

where $q_{1}$ and $q_{2}$ are charged particles

k =Coulombs constant

r = distance between two charges

And gravitational force is given by

F = $\frac{G.m_{1}.m_{2}}{r^{2}}$

where $m_{1}$ and $m_{2}$ are masses

G =Garvitation constant

r = distance between two masses

Now since the planets, stars and galaxies are electrically neutral, therefore they have zero electrical charge and so electro magnetic forces have no affect on these planets, stars and heavenly bodies.

Whereas the masses of the heavenly bodies are very large, so they are largely affected by the gravitational force since Gravitational force is directly proportional to the product of the masses of a body.

Therefore, though the electromagnetic force is stronger than the gravitational force, the electromagnetic force does not dominate the forces in the heavenly bodies as they as not electrically charged.

8 0

4 years ago

In the Olympic shot-put event, an athlete throws the shot with an initial speed of 12.0 m/s at a 40.0 ∘ angle from the horizonta

Gre4nikov [31]

Answer:

Explanation:

given,

initial speed of the shot = 12.0 m/s

angle = 40°

height at which shot leaves her hand = 1.80 m

v_x = 12 cos 40° = 9.19 m/s

v_y = 12 sin 40° = 7.71 m/s

time to reach maximum height =

= $\dfrac{v_y}{g}$

= $\dfrac{7.71}{9.8}$

= 0.787 s

$h = v_y t + \dfrac{1}{2}gt^2$

h = 7.71 × 0.787 - 0.5 × 9.81 × 0.787²

h = 3.03 m

the maximum height attain = 3.03 + 1.8 = 4.83 m

now free fall from the maximum height

$h =\dfrac{1}{2}gt^2$

$4.83 = \dfrac{1}{2}\times 9.8 \times t^2$

t = 0.9928 s

total time = 0.9928 + 0.787 = 1.7798 s

range =

d = vₓ t

d = 16.36 m

8 0

4 years ago

Use the scientific method to disprove the theory that “the Earth is the center of the universe.”

Pachacha [2.7K]

Why would we assume that Earth is the center of the the Universe in the first place?

Besides the fact the Earth contains life, it is no different from any other planet that we have ever seen, nor is the solar system in which it resides. There is no reason in the first place to assume its placement in the universe is different either.

7 0

4 years ago

2 kg<br> Use 10 m/s2 for g

Iteru [2.4K]

Answer:

See below

Explanation:

At point A the PE = mgh = 2 * 10 * 1 = 20 J

at point B, all of the PE , 20 J , is converted to Kinetic Energy

KE = 1/2 m v^2

20 = 1/2 (2)(v^2 )

20 = v^2 v = sqrt 20 = 4.47 m/s

for the friction part

vf = vo t + 1/2 a t^2 vf = final velocity = 0 (stopped)

vo = original velocity = 4.47 m/s

a = -1 m/s^2

0 = 4.47 t + 1/2 (-1) t^2

- .5t^2 + 4.47 t = 0

t ( -.5t+ 4.47) = 0 shows t = 4.47/.5 = 8.9 seconds

6 0

2 years ago

Electric current is _____.

Maksim231197 [3]

Electric current is the movement of the electrons caused by potential difference. For example, in a circuit, the electrons in the bulb will not move without the potential difference or voltage. When there is voltage, electric current occurs because there is a driving force for the electrons in the wire to move.

4 0

3 years ago