(a) Keck-I has a 10m diameter mirror. HST (Hubble Space Telescope) has a 2.4m mirror.

What is the ratio of the light gathering power of Keck-I to the light-gathering power of HST?

[Compute the ratio (light gathering power of Keck)/(light gathering power of HST) and express as a decimal. Do not use scientific notation.]

(b) What is the ratio of the angular resolution limit of Keck to the angular resolution limit of HST? (Assume they are both observing at the same wavelength.)

[Compute the relevant ratio Keck/HST, express as a decimal, and enter below.]

(c) HST orbits at an altitude of 559 km above the Earth's surface. Assume its orbit is circular.

Compute its orbital period in hours.

(d) Compute its orbital speed (in km/s).

(e) If a satellite like Hubble was looking down at the Earth instead of up, what is the smallest physical size (in cm) on the Earth’s surface that it could resolve? [Hint: assume you are using the visible spectrum.]

The potential at the center of a uniformly charged ring is 44 kV , and 11 cm along the ring axis the potential is 31 kV .

Find the ring's radius.

Find the ring's total charge.

Which of these are actual evidence for the existence of a black hole in the center of the Milky Way, and which are not?

Stars are observed to disappear into the black hole

Bright quasar emission is detected from the center of the galaxy

Telescopes have been used to take high resolution images of the black hole's event horizon

Astronomers observe an extremely bright and compact radio source

The closest approach of stellar orbits near the center of the galaxy indicate the object is smaller than the solar system

Stellar velocities near the center of the galaxy indicate 4 million times the mass of the sun inside their orbit

Find all possible values of the following for a hydrogen atom in a 3d state.

I have the value of L as 2.57e-34 which is correct.

L_z. (Enter your answers from smallest to largest. Enter NONE in any unused answer blanks. Use the following as necessary: h(bar))

There are 4 boxes and the 2nd and 3rd are 1 and 2 but i cannot get the first and fourth boxes.

θ. (Enter your answers from smallest to largest. Enter NONE in any unused answer blanks.)

there are 8 boxes for this part.

Thank you!

A girl is sitting near the open window of a train that is moving at a velocity of 22.00 m/s to the east. The girl's uncle stands near the tracks and watches the train move away. The locomotive whistle emits sound at frequency 770.0 Hz. The air is still. (Use 343 m/s for the speed of sound in air for all parts of this question.) (a) What frequency does the uncle hear? Hz (b) What frequency does the girl hear? Hz (c) A wind begins to blow from the east at 22.00 m/s. What frequency does the uncle now hear? Hz (d) What frequency does the girl now hear? Hz

1. A 200 g aluminum calorimeter contains 500 g of water at 20 C. A 100 g piece of ice cooled to -20 C is placed in the calorimeter.

1. Find the final temperature of the system, assuming no heat losses. (The specific heat of ice is 2.0 kJ/kg K)
2. A second 200 g piece of ice at -20 C is added. How much ice remains in the system after it reaches equilibrium?
3. Would your answer to part b be different if both pieces of ice were added at the same time?

(specific heat of aluminum is 0.9 kJ/kg K and water is 4.18 kJ/kg K)

At takeoff a commercial jet has a 70.0 m/s speed. Its tires have a diameter of 0.400 m.

(a) At how many rpm are the tires rotating?
  rpm
(b) What is the centripetal acceleration at the edge of the tire?
  m/s²
(c) With what force must a determined 10^-15 kg bacterium cling to the rim?
N
(d) Take the ratio of this force to the bacterium's weight.
(force from part (c) / bacterium's weight)

(a) A 23.0 kg child is riding a playground merry-go-round that is rotating at 45.0 rpm. What centripetal force must she exert to stay on if she is 2.50 m from its center?
  N
(b) What centripetal force does she need to stay on an amusement park merry-go-round that rotates at 3.00 rpm if she is 5.00 m from its center?
  N
(c) Compare each force with her weight.
  (force from part (a) / weight)
  (force from part (b) / weight)

All of these answers wrong someone please help me.

Special relativity

Q: What is Einstein’s special relativity principle?

Q: What is the relativity of simultaneity?

Q: What is time dilation? Length contraction?

Q: Why is there a cosmic speed limit?

A skeet shooter aims at a clay pigeon. The muzzle velocity of the rifle is 700 mph and the man holds the rifle such that the end of the gun is 6 ft off the ground. Assuming that the speed of the skeet is insignificant relative to the speed of the bullet, determine the angle at which the man needs to hold the rifle in order to hit a clay pigeon that is 50 yards away and at an altitude of 30 ft.

How long will it take to form a thickness of 10 cm of ice on the surface of a lake when the air temperature is -15°C? The thermal conductivity K of ice is 4 x 10^-3 cal/s*cm*°C and its density is 0.92 g/cm^3

1. A 7130-kg car is travelling at 24.8 m/s when the driver decides to exit the freeway by going up a ramp. After coasting 418 m along the exit ramp the car\'s speed is 12.4 m/s, and it is h = 12.5 m above the freeway. What is the magnitude of the average drag force exerted on the car?

2. The superheroine Xanaxa, with a mass of 66.3 kg, is in a hair-raising chase after the 74.3-kg arch-villain Lexlax. She leaps from the ground to the top of a 195-m-high building, then dives off and comes to rest at the bottom of a 16.7-m-deep excavation, where she finds Lexlax and neutralizes him. Does all this bring about a net gain or a net loss of gravitational potential energy? Loss or Gain

By how much? Answer with a positive number. Take g = 9.81 m/s2.

3.Tom has built a large slingshot, but it is not working quite right. He thinks he can model the slingshot like an ideal spring, with a spring constant of 75.0 N/m. When he pulls the slingshot back 0.305 m from a non-stretched position, it just doesn\'t launch its payload as far as he wants. His physics professor \"helps\" by telling him to aim for an elastic potential energy of 14.5 Joules. Tom decides he just needs elastic bands with a higher spring constant. By what factor does Tom need to increase the spring constant to hit his potential energy goal?

During a followup conversation, Tom\'s physics professor suggests that he should leave the slingshot alone and try pulling the slingshot back further without changing the spring constant. How many times further than before must Tom pull the slingshot back to hit the potential energy goal with the original spring constant?

4. An adult dolphin weighs around 1610 N. How fast must he be moving as he leaves the water vertically in order to jump to a height of 3.50 m? Ignore air resistance.

5. Nate the Skate was an avid physics student whose main non-physics interest in life was high-speed skateboarding. In particular, Nate would often don a protective suit of Bounce-Tex, which he invented, and after working up a high speed on his skateboard, would collide with some object. In this way, he got a gut feel for the physical properties of collisions and succeeded in combining his two passions.* On one occasion, the Skate, with a mass of 119 kg, including his armor, hurled himself against a 801-kg stationary statue of Isaac Newton in a perfectly elastic linear collision. As a result, Isaac started moving at 1.37 m/s and Nate bounced backward. What were Nate\'s speeds immediately before and after the collision? (Enter positive numbers.) Ignore friction with the ground. Before:_______m/s, After:_______m/s

*By the way, this brief bio of Nate the Skate is written in the past tense, because not long ago he forgot to put on his Bounce-Tex before colliding with the Washington Monument in a perfectly inelastic collision. We will miss him.

Two speakers are facing each other, 4.00 meters apart, in phase and playing a sound with frequency 170HZ. Find the distance from the center point to the nearest point where totally destructive interference occurs.

A 4.00-kg block rests on an inclined plane that has an inclination angle of 31.3o. A string attached to this block, goes uphill and over a frictionless pulley, and then is attached to a hanging block of mass M. The inclined plane has coefficients of friction μs = 0.22 and μk = 0.13.

Draw a real world picture of this scenario.

Draw the free body diagrams for each of the blocks.

Show how to determine the mass M that will cause the blocks to start moving.

Once the blocks are moving, show how to determine the acceleration of the blocks.

Show how to determine the speed and distance that the blocks have moved after 5.55 seconds

(1 point) Suppose a pendulum with length L (meters) has angle θ (radians) from the vertical. It can be shown that θ as a function of time satisfies the differential equation:

((d^2)θ)/(dt^2))+(g/L)sinθ=0

where g=9.8/sec is the acceleration due to gravity. For small values of θ we can use the approximation sin(θ)∼θ, and with that substitution, the differential equation becomes linear.

A. Determine the equation of motion of a pendulum with length 0.5 meters and initial angle 0.5 radians and initial angular velocity dθ/dt 0.4 radians/sec.

B. At what time does the pendulum first reach its maximum angle from vertical? (You may want to use an inverse trig function in your answer)

seconds

C. What is the maximum angle (in radians) from vertical?

D. How long after reaching its maximum angle until the pendulum reaches maximum deflection in the other direction? (Hint: where is the next critical point?)

seconds

E. What is the period of the pendulum, that is the time for one swing back and forth?

seconds

Imagine that you have obtained spectra for several galaxies and have measured the observed wavelength of a hydrogen emission line that has a rest wavelength of 656.3 nanometers. Here are your results:

Galaxy 1: Observed wavelength of hydrogen line is 658.7 nanometers

Galaxy 2: Observed wavelength of hydrogen line is 664.2 nanometers.

Galaxy 3: Observed wavelength of hydrogen line is 683.6 nanometers.

Part D: Estimate the distance to each galaxy from Hubble's law. Assume that H0=22km/s/Mly.

Express your answers using two significant figures. Enter your answers numerically separated by commas.

(dgalaxy1, dgalaxy2, dgalaxy3 = *Answer* Mly)