<span>This
is because astronomers have discovered that
the Crab Nebula is 6500 light years from earth. This means it takes 6500 earth years
for light to get from the Crab Nebula to
earth. Therefore, if we are able to observe the
Crab Nebula and beyond it then it means that earth has been in existence for 6500 years and
over. </span>
Answer:
La velocidad de la luz en el vacío es una constante universal con el valor de 299 792 458 m/s (186 282,397 mi/s),aunque suele aproximarse a 3·108 m/s. Se simboliza con la letra c, proveniente del latín celéritās (en español, celeridad o rapidez).
¿Cuál es la consecuencia que a velocidad de la luz sea constante?
Respuesta. En modificaciones del vacío más sutiles, como espacios curvos, efecto Casimir, poblaciones térmicas o presencia de campos externos, la velocidad de la luz depende de la densidad de energía de ese vacío.
Answer:
Explanation:
Given that,
Frequency of a radio antenna is 1 MHz
Power, P = 21 kW
We need to find the the waves intensity 25 km from the antenna
. The object emits intenisty evenly in all direction. It can be given by :
So, the wave intensity 25 km from the antenna is 
.
Answer:
a)1.37 s
b)∞ ( Infinite)
Explanation:
Given that
L= 47 cm ( 1 m =100 cm)
L= 0.47 m
a)
On the earth :
Acceleration due to gravity = g
We know that time period of the simple pendulum given as
Here
Now by putting the values
T=1.37 s
b)
Free falling elevator :
When elevator is falling freely then
( This is case of weightless motion)
Therefore
T=∞ (Infinite)
Rw/Ra = MA
18cm/2cm= MA
MA = 9
This means that Fi is 1/9 of the force applied to the axil. The distance travelled by Rw is 9 times more than Ri is that you move 9 times more when turning the wheel using Rw.
Put more simply
Rw/Ra = Fa/Fw
- Rw = Radius of the wheel
- Ra = Radius of the axil
- Fa = Force delivered on the axil
- Fw = Force delivered by the wheel
