What is the primary source of a sound?
C. A vibration
Which of the following best describes reverberation?
A. The wavefronts become mixed and broken up due to contact with a rough or irregular surface.
_______ occurs when a body’s molecular wavelength sends vibrations to another body, resulting in the production of another sound wave.
D. Resonance
Which of the following is an example of the Doppler effect?
B. Vibrations from a tuning fork pass through the air and cause a nearby dish of water to produce ripples of the same frequency.
In Sir Isaac Newton's time in the early 1700s, what was the general consensus among scientists on the properties of light?
D. Light is composed of particles and travels in a straight line.
If the angle of incidence of a light source to a shiny surface is 30 degrees, what will the angle of reflection be?
C. 30 degrees
If a material has a high index of refraction, it has a
B. high optical density, and light travels more slowly through it.
Which of the following statements regarding the visible spectrum of light is accurate?
D. It has the longest wavelength of all types of waves along the electromagnetic spectrum.
If you were to combine a beam of blue light and a beam of yellow light, what would the result be?
C. Green light
The type of light waves that living things give off naturally is called
D. visible light.
When you're standing in a pool in the summertime, and your leg looks shorter under the water than in air, this is an example of light
B. refraction.
Carbon compounds move through plants and animals, the ocean, the air, and throughout our planet. Carbon present in our atmosphere as carbon dioxide contributes to the"Greenhouse Effect" and related global warming. Carbon cycle used to described the flow of carbon in various form such as carbon dioxide CO2, organic matter, and carbonates through the atmosphere, body of water, terrestrial biosphere, and lithosphere.
1) The forces of molecules is how strong they are being held together. Now, we know that solid is the last one, because it's particles are held CLOSELY and VERY TIGHTLY together, which is why it has a definite shape.And last of all, a gas's particles are held freely, which is why it has no shape. So the answer would be:- gas, liquid, solid
3) The state of matter that does not have a definite shape, but has a definite volume is a liquid. So the answer is :- liquid
7) False, an endothermic reaction is when it absorbs energy, and as we know that in a chemical reaction as the following, it tends to be an exothermic reaction, meaning that is releases energy. So the answer is:- FALSE
8) Gases have particles that are far apart (freely) and move fast. So the answer is:- They are moving very fast and are far apart.<span> </span>
Angular momentum is given by the length of the arm to the object, multiplied by the momentum of the object, times the cosine of the angle that the momentum vector makes with the arm. From your illustration, that will be:
<span>L = R * m * vi * cos(90 - theta) </span>
<span>cos(90 - theta) is just sin(theta) </span>
<span>and R is the distance the projectile traveled, which is vi^2 * sin(2*theta) / g </span>
<span>so, we have: L = vi^2 * sin(2*theta) * m * vi * sin(theta) / g </span>
<span>We can combine the two vi terms and get: </span>
<span>L = vi^3 * m * sin(theta) * sin(2*theta) / g </span>
<span>What's interesting is that angular momentum varies with the *cube* of the initial velocity. This is because, not only does increased velocity increase the translational momentum of the projectile, but it increase the *moment arm*, too. Also note that there might be a trig identity which lets you combine the two sin() terms, but nothing jumps out at me right at the moment. </span>
<span>Now, for the first part... </span>
<span>There are a few ways to attack this. Basically, you have to find the angle from the origin to the apogee (highest point) in the arc. Once we have that, we'll know what angle the momentum vector makes with the moment-arm because, at the apogee, we know that all of the motion is *horizontal*. </span>
<span>Okay, so let's get back to what we know: </span>
<span>L = d * m * v * cos(phi) </span>
<span>where d is the distance (length to the arm), m is mass, v is velocity, and phi is the angle the velocity vector makes with the arm. Let's take these one by one... </span>
<span>m is still m. </span>
<span>v is going to be the *hoizontal* component of the initial velocity (all the vertical component got eliminated by the acceleration of gravity). So, v = vi * cos(theta) </span>
<span>d is going to be half of our distance R in part two (because, ignoring friction, the path of the projectile is a perfect parabola). So, d = vi^2 * sin(2*theta) / 2g </span>
<span>That leaves us with phi, the angle the horizontal velocity vector makes with the moment arm. To find *that*, we need to know what the angle from the origin to the apogee is. We can find *that* by taking the arc-tangent of the slope, if we know that. Well, we know the "run" part of the slope (it's our "d" term), but not the rise. </span>
<span>The easy way to get the rise is by using conservation of energy. At the apogee, all of the *vertical* kinetic energy at the time of launch (1/2 * m * (vi * sin(theta))^2 ) has been turned into gravitational potential energy ( m * g * h ). Setting these equal, diving out the "m" and dividing "g" to the other side, we get: </span>
<span>h = 1/2 * (vi * sin(theta))^2 / g </span>
<span>So, there's the rise. So, our *slope* is rise/run, so </span>
<span>slope = [ 1/2 * (vi * sin(theta))^2 / g ] / [ vi^2 * sin(2*theta) / g ] </span>
<span>The "g"s cancel. Astoundingly the "vi"s cancel, too. So, we get: </span>
<span>slope = [ 1/2 * sin(theta)^2 ] / [ sin(2*theta) ] </span>
<span>(It's not too alarming that slope-at-apogee doesn't depend upon vi, since that only determines the "magnitude" of the arc, but not it's shape. Whether the overall flight of this thing is an inch or a mile, the arc "looks" the same). </span>
<span>Okay, so... using our double-angle trig identities, we know that sin(2*theta) = 2*sin(theta)*cos(theta), so... </span>
<span>slope = [ 1/2 * sin(theta)^2 ] / [ 2*sin(theta)*cos(theta) ] = tan(theta)/4 </span>
<span>Okay, so the *angle* (which I'll call "alpha") that this slope makes with the x-axis is just: arctan(slope), so... </span>
<span>alpha = arctan( tan(theta) / 4 ) </span>
<span>Alright... last bit. We need "phi", the angle the (now-horizontal) momentum vector makes with that slope. Draw it on paper and you'll see that phi = 180 - alpha </span>
<span>so, phi = 180 - arctan( tan(theta) / 4 ) </span>
<span>Now, we go back to our original formula and plug it ALL in... </span>
<span>L = d * m * v * cos(phi) </span>
<span>becomes... </span>
<span>L = [ vi^2 * sin(2*theta) / 2g ] * m * [ vi * cos(theta) ] * [ cos( 180 - arctan( tan(theta) / 4 ) ) ] </span>
<span>Now, cos(180 - something) = cos(something), so we can simplify a little bit... </span>
<span>L = [ vi^2 * sin(2*theta) / 2g ] * m * [ vi * cos(theta) ] * [ cos( arctan( tan(theta) / 4 ) ) ] </span>
Answer: (2) 108 C
Explanation:
Electric charge of 1 coulomb has said to have passed when a current of 1 Ampere is passed for 1 second.
Q= charge in coloumb = ?
I = current in amperes = 0.120 A
t= time in seconds = 900 sec