Answer:
A lens
Explanation:
A lens forms images when light passes Through it bending the rays of in the process.A phenomena called refraction and the speed of light changes in the process because it enters a medium since it's wavelength is reduced.
The whole definition of frequency is: <em>How often something happens. </em>
Especially referring to something that happens over and over and over and over.
One example is Choice-C: How often the particles of a medium vibrate.
"Frequency" comes from the word "frequent". That means "often", and "frequency" just means "often-ness" ... HOW often the thing happens.
Some other examples:
Frequency of jump-roping . . . maybe 60 per minute .
Frequency of rain . . . maybe 5 per month .
Frequency of an AM radio station . . . maybe 1 million waves per second.
(If it's something <u><em>per second</em></u>, then we call it "Hertz". That's not for the car rental company. It's for Heinrich Hertz, the German Physicist who was the first one to prove that electromagnetic waves exist. He sent radio waves all the way ACROSS HIS LABORATORY and detected them at the other side ( ! ), in 1887.)
Frequency of the wiggles in the sound wave coming out of a trumpet playing the note ' A ' . . . 440 Hertz.
Frequency of sunrise and the Chicago Tribune newspaper . . . 1 per day
Frequency of the cycle of Moon phases and an average human woman's ovulation cycle: 1 per 29.531 days, 1 per ~28 days .
<span>Why is the weight of an object more on Earth than on the Moon? i would say c</span>
Answer:+1.25 m/s
Explanation:
Given
mass of ice skater M=70 kg
mass of ball m=10 kg
the initial velocity of the ball 
Conserving linear momentum
![M\times0+m\timesu_1=(M+m)v\quad \quad [v=\text{combined velocity of skater and ball}]](https://tex.z-dn.net/?f=M%5Ctimes0%2Bm%5Ctimesu_1%3D%28M%2Bm%29v%5Cquad%20%5Cquad%20%5Bv%3D%5Ctext%7Bcombined%20velocity%20of%20skater%20and%20ball%7D%5D)
Therefore the velocity of the person holding the ball is 1.25 m/s
This collision represents the perfectly inelastic collision where particles stick together after the collision.
