Answer:
(B) Dark energy does not exist and there is much more matter than current evidence suggests.
Explanation:
The repulsive force which is accelerating expansion of the universe is called as dark energy. Most of matter present in the universe is the dark matter of about eighty five percent.
So, a collapsing universe would not have the dark energy and there is more matter which is not the dark matter. This theory is rejected because expansion of the universe is observable.
Answer:
a)
b)
Explanation:
a)
The width of the central bright in this diffraction pattern is given by:
when m is a natural number.
here:
- m is 1 (to find the central bright fringe)
- D is the distance from the slit to the screen
- a is the slit wide
- λ is the wavelength
So we have:
b)
Now, if we do m=2 we can find the distance to the second minima.
Now we need to subtract these distance, to get the width of the first bright fringe :
I hope it heps you!
The bicycle is a distance <em>x</em> away from the wall at time <em>t</em> according to
<em>x</em> = 10 m + (4 m/s) <em>t</em> + 1/2 (12 m/s²) <em>t</em> ²
so that after <em>t</em> = 8 s, it will be
<em>x</em> = 10 m + (4 m/s) (8 s) + 1/2 (12 m/s²) (8 s)² = 426 m
away from the wall.
You said that the useful output power from the model is 6 watts. You also said that the model is 80% efficient. We have no reason to doubt your word, so we know that
(useful output) / (input power) = 80% or 0.8
(6 watts) / (input power) = 0.8
Multiply each side by (input power): 6 watts = (0.8) (input power)
Divide each side by 0.8 : Input power = (6 watts/ 0.8)
<em>Input power = 7.5 watts</em>
