Answer:
10. B
13. It's actually 30 seconds but 20 comes closest so B
14. B, any type of stretching is good before you perform any type of physical activity because it loosens up the muscles
15. D, all of the above
Explanation:
I have done many sports in my life and am still very active, I grew to know most of these things through the years.
The period of any wave is the time it takes for its angle
to go from zero to 2pi .
The 'sin' function is a wave. The angle of this one is (8pi t).
When t=0, the angle is zero.
Wonderful.
Now, how long does it take for the angle to grow to 2pi ?
I*n other words, when is (8pi t) = 2pi ?
Divide each side by '2pi': . . . . . 4 t = 1
Divide each side by ' 4 ': . . . . . t = 1/4
And there you are. Every time 't' grows by 1/4, (8pi t) grows by 2pi.
So if you graph this simple harmonic motion described by 'd', you'll
see the graph wiggle up and down with a period of 1/4 .
Well, basically both Cheryl and Keaton is right.
matter is described as Physical substance that possessed space and mass.
But the thing is, one matter is very small in size and cannot be seen with naked eyes. But everything around us are made by matters
hope this helps
Answer:
0.18216 T
Explanation:
N = Number of turns = 219
A = Area = 
r = Radius = 1 cm
= Angular speed = 
Maximum emf is given by

The strength of the magnetic field is 0.18216 T
1. it is difficult to search for it . Because infrared rays will never penetrate through earth atmosphere.
2. we are unaware of how it looks like and we only know it is red and will glow . A damaged star also looks like this.
3. Dust also makes is hard to detect Dyson spheres . So we will get confused between Dyson sphere and a star surrounded by dust.