I REALLY NEED TO LEARN THIS PROBLEM INSIDE OUT. PLEASE BE AS DERCRIPTIVE AND CLEAR AS YOU CAN BE PLEASE ( AS IF YOU WERE TEACHING A PERSON WHO KNOWS NOTHING ABOUT PHYSICS) thank so much

1. a rock is dropping from a sea cliff and the sound of it striking the ocean is heard 3.4 s later. if the speed of sound is 340 m/s, how high is the cliff?

A 29.0-kg block is initially at rest on a horizontal surface. A horizontal force of 76.0 N is required to set the block in motion, after which a horizontal force of 57.0 N is required to keep the block moving with constant speed.

(a) Find the coefficient of static friction between the block and the surface.

(b) Find the coefficient of kinetic friction between the block and the surface.

Two loudspeakers are located 3.50 m apart on an outdoor stage. A listener is 19.3 m from one and 20.2 m from the other. During the sound chek, a signal generator drives the two speakers in phase with the same amplitude and frequency. The transmitted frequency is swept through the audible range (20 Hz - 20 kHz). The speed of sound in the air is 343 m/s. What are the three lowest frequencies that give minimum signal (destructive interference) at the listener's location?

(a)  Hz (lowest)

(b)  Hz (second lowest)

(c)  Hz (third lowest)

What are the three lowest frequencies that give maximum signal (constructive interference) at the listener's location?

(d)  Hz (lowest)

(e)  Hz (second lowest)

(f)  Hz (third lowest)

You were asked to include both your standard error and your percent difference when formally reporting your experimental results. What do they represent? Do you think they should be included in scientific reporting?

1. Student A performs a similar experiment with a different object and obtains the following direct measurements of the mass of their object: [21.06g, 20.98g, 21.12g, 21.21g, 21.10g]
   a. Calculate and report the average, standard deviation, and standard error of Student A’s mass

   measurements using the 1D Stats macro.
   b. Add one gram to each of the five mass values in part (a). Repeat your 1D Stats calculation and

   report the average, standard deviation, and standard error. Which values have changed and which have not? Be sure to show your work, including the new 1D Stats results. The one gram difference in each measurement represents a systematic error in the data.

   c. Change the masses back to their original values and now add a 10 gram systematic error to the first two values only. Repeat your 1D Stats and note what has and has not changed.

   d. If the only data you saw was the data table generated in part (d), do you feel you would have been able to catch the systematic errors in part (d)? Explain in one to three sentences.

Show how the “Law of Cosines” derives from finding the magnitude of the difference of two vectors. As a consequence, show that if two vectors are perpendicular – then the law of cosines becomes the Pythagorean theorem.

You are handed a rod that is three times as dense on one end as it is on the other end. Find the moment of inertia when the axis of rotation is about the heavy end, and find the moment of inertia when the axis of rotation is about the light end.

A 1025 car and a 2150 pickup truck approach a curve on the expressway that has a radius of 246 m. At what angle should the highway engineer bank this curve so that vehicles traveling at 71.9 mph can safely round it regardless of the condition of their tires? Should the heavy truck go slower than the lighter car? As the car rounds the curve at 71.9 mph, find the normal force on the car due to the highway surface. As the truck rounds the curve at 71.9 mph, find the normal force on the truck due to the highway surface.

1. How did Hubble show the nebulae are separate island universes?
2. Which types of galaxies have the large amount of star formation, spirals or ellipticals? Why is this the case?
3. What is the evidence for black holes in the centers of galaxies?
4. If H=70km/s/Mpc and a galaxy is receding at 10000 km/s, how far away is it? Show your work.
5. Why do we see only bright spirals and ellipticals in distant clusters of galaxies? Is this really all the galaxies in these clusters?

Vector subtraction is the addition of a vector in the opposite direction. For Cases A, B, and C, what would be the result of ⃗R=⃗A−⃗B . You may compute the answer by analytical methods, but show your work as well as the answer.

CASE A: Vector A: 2.94N at 20 degrees Vector B: 1.96N at 110 degrees.

CASE B: Vector A: 1.96N at 20 degrees Vector B: 1.71N at 65 degrees
CASE C: Vector A: 1.96N at 20 degrees Vector B: 1.96N at 290 degrees

Part 1: Spectrometer

Please follow the instructions to construct a refractometer and answer the corresponding questions.

The instructions below describe how to build a spectrometer. Here is a link if you wish to view the site where the instrcutions are from.  Spectroscope

How to make a spectroscope

What we will need:

A CD or DVD that can be sacrificed to this project. We won't damage it, but getting it back will involve destroying our spectroscope. Old software CDROMs work great, and some can be had for free from internet service providers like AOL.

A cardboard box. An 8 inch cube works fine, but any size that can hold a CD or DVD disk will do.

Two single edged razor blades. These can be found in paint or hardware stores.

A small cardboard tube, the kind used as a core to wrap paper on.

Some cellophane tape.

Some aluminum tape (found in hardware stores), or some aluminum foil and glue.

Our spectroscope has three main parts. There is a slit made from two razor blades, a diffraction grating made from a CD disk, and a viewing port, made from a paper tube.

To make sure that all three parts are lined up properly, we will use the CD disk as a measuring device, and mark the spots where the slit and the viewing port will go.

Set the CD disk on top of the box, about a half inch from the left edge, and close to the box's bottom, as shown in the photo. Use a pen to trace the circle inside the CD disk onto the box. This mark shows us where the paper tube will go.

Now place the paper tube on the box, centered over the circle we just drew. Draw another circle on the box by tracing the outline of the paper tube.

Move the paper tube over a little bit. A half-inch is probably fine -- in the photo I placed it much farther to the right than necessary, but the aluminum tape covered up the mistake nicely. Trace another circle around the paper tube. These circles will tell us where to cut the box.

Now cut an oval out of the box with a sharp knife. The oval will allow the paper tube to enter the box at an angle.

The next step is to make the slit. Turn the box one quarter turn so the oval we just cut is to the right. Using the CD disk again, draw another small circle close to the left side of the box.

The slit will be on the far left of the box. Cut a small rectangle out of the box at the height marked by the small circle we made with the CD disk. The rectangle should be about a half inch wide, and two inches high.

Carefully unwrap the two razor blades, and set them over the rectangular hole. Make their sharp edges almost touch. Tape the razor blades to the box, being careful to leave a gap between the sharp edges that is nice and even, and not wider at the top or bottom.

Next, set the box right-side-up, with the slit towards you. Now tape the CD disk onto the back wall of the box. The rainbow side should face you, with the printed side touching the cardboard. The photo shows the disk a little too far to the left. The left edge of the disk should be the same distance from the left of the box as the slit is.

Now seal up any places on the box where light might leak in. Use the aluminum tape for this. You can also use aluminum foil for this purpose if you don't have any aluminum tape.

The last step is to use the aluminum tape to attach the paper tube. The aluminum tape will make a light-tight seal around the tube. To make sure the angle is correct, hold the slit up to a light, and look through the paper tube, adjusting it until you can see the full spectrum from red to purple.

Once you have assembled your spectrometer with the instructions in the lecture and above, use it to examine the spectra of three different light sources. Make sure that at least one of them is the sun or moon, but the others can be incandescent lights, compact fluorescent bulbs, LED lights, halogen or xenon bulbs, televisions, computer screens, candles, fireplaces, etc.

Then, answer the following questions in a separate document:

Describe the differences in appearance among the three spectra.

What feature of the light source do the spectra represent? In other words, what is it that you are actually analyzing?

Why do you think spectrometers are so valuable for studying celestial objects?

Part 2: Estimating the Number of Visible Stars in the Night Sky

For this, you will need an empty toilet roll and a clear, dark night. Before you start, jot down the number of stars that you think you can see in the night sky.

Aim your toilet roll at a part of the sky well above the horizon to avoid any haze pollution. Hold your roll steady and allow your eyes to get used to the light for a few seconds. Count the number of stars that you can see within through the roll. Do this four more times in other parts of the sky, and average the five counts.

The viewing diameter of a toilet roll is about 1/135th of the entire sky, at least for a relatively flat area. Mountains, buildings or large trees will obscure some of the sky. To determine the number of visible stars, multiply your average by 135.

Answer the following questions:

4. How similar is this to your original estimation?

5. What percentage of our galaxy do you think that we can see with the naked eye from Earth?

Part 3: Solar System

Please answer the following questions:

6. What percentage of our galaxy do you think that we can see with the naked eye from Earth?

7. Why do you think that the inner planets are relatively close together, but the outer planets are spaced so widely apart?

8. Why do you think that the gaseous planets are gaseous, but the inner planets are not?

An exhausted bicyclist pedals somewhat erratically when exercising on a static bicycle. The angular velocity of the wheels follows the equation ω(t)=at−bsin(ct)fort≥0, where t represents time (measured in seconds), a = 0.500 rad/s2 , b = 0.250 rad/s and c = 2.00 rad/s .

Part A

There is a spot of paint on the front wheel of the bicycle. Take the position of the spot at time t=0 to be at angle θ=0 radians with respect to an axis parallel to the ground (and perpendicular to the axis of rotation of the tire) and measure positive angles in the direction of the wheel's rotation. What angular displacement θ has the spot of paint undergone between time 0 and 2 seconds?

Part B

Express the angular displacement undergone by the spot of paint at t=2 seconds in degrees. Remember to use the unrounded value from Part A, should you need it.

Express your answer in degrees using three significant figures.

Part C

What distance d has the spot of paint moved in 2 seconds if the radius of the wheel is 50 centimeters?

Part D

Which one of the following statements describes the motion of the spot of paint at t=2.0 seconds?

Which one of the following statements describes the motion of the spot of paint at  seconds?

In a drag race, the position of a car as a function of time is given by x=bt2, with b = 2.045m/s2 . In an attempt to determine the car's velocity midway down a 400-m track, two observers stand at the 165-m and 235-m marks and note the time when the car passes.What value do the two observers compute for the car's velocity over this 70m stretch?

The reflecting surfaces of two intersecting flat mirrors are at an angle of 57?, as shown in the figure. A light ray strikes the horizontal mirror at an angle of 57? with respect to the mirror

You are given displacement equation for object in SHM as: x(t)=1.5cos(3.0t) cm.  

a) The period of this oscillation is:    [ Select ] ["2.1 sec", "3 sec", "1.5 sec", "0.48 sec"]         

b) The amplitude of the motion is:        [ Select] ["0.75 m", "1.5 m", "3.0 m"]      

c) The maximum velocity is: [ Select ] ["28 m/s", "4.5 m/s", "0.72 m/s"]      

d) The displacement at t = 0.5 s is   [ Select ]   ["0.12 m", "-0.78 m", "1.5 m"]