consider a spacecraft in an elliptical orbit around the earth. At the low point, or perigee, of its orbit, it is 300 km above the earth's surface; at the high point or apogee, it is 2500 km above the earth's surface.

Part A: find ratio of the spacecraft's speed at perigee to its speed at apogee?

(V_perigee / V_{apogee) = .....}

Part B: find the speed at the apogee?

V apogee = ........ m/s

Part C: find speed at perigee?

V perigee = ..... m/s

(I only have 1 try left in mastering please help me thanks)

A 63 kg man weighs himself at the north pole and at the equator. Assume the Earth is a perfectly spherical.

1.a Which scale reading is higher? at the North Pole or at the equator

1b. By how much?Express your answer with the appropriate units.

Having trouble with these:

1. One of the important struggles of pioneering astronomers was trying to understand how big our galaxy is, and where the Sun is located in our galaxy. Explain how RR Lyrae stars and globular clusters were used by Harlow Shapley to answer both these questions.

2. Radio astronomy has been critical for determining the structure of our galaxy. Why is it more effective for this purpose than visible light astronomy?

3. Charlie and Monica are arguing about spiral arms. Charlie believes that spirals arms are regions where active star formation takes place, and are like “traffic jams” where the gas and dust is dense. Monica believes that the spiral arms of a galaxy are like a rigid spinning pinwheel, and the gravitational attraction of the stars to one another keeps them in rigid shape, like sparkles glued to a pinwheel. Whose explanation is more accurate, and why?

Captain Jack Sparrow is steering the Black Pearl during battle, and he needs to turn the ship around quickly. The helm (steering wheel) of the Pearl has handles that extend to a radius of 50 cm. Sparrow starts spinning the helm from rest, accelerating it at a constant 5 degrees/s2 . What is the tangential velocity of the handles in m/s when the radial acceleration of the helm is equal to the tangential acceleration of its handles?

Answer: 0.15 m/s

In a Young's double-slit experiment the wavelength of light used is 469 nm (in vacuum), and the separation between the slits is 2.1 × 10^-6 m. Determine the angle that locates (a) the dark fringe for which m = 0, (b) the bright fringe for which m = 1, (c) the dark fringe for which m = 1, and (d) the bright fringe for which m = 2.

a) Is the optical axis of a birefringent crystal simply a line or an address in space?
Does it have direction and sense like an arrow?
b) Explain what the crystals are: trigonal, tetragonal, hexagonal, triclinic, monoclinic and orthorhombic.
c) Explain in detail what is fluorescence and phosphorescence.

Question 1. Explain, on the atomic level, the physical mechanism underlying two of the three forms of magnetic materials described in the text, paramagnetic, diamagnetic, and Ferromagnetic. 2. Aluminum is paramagnetic. Why won't a typical refrigerator magnet stick to an aluminum can? 3. Describe how bar magnets produce a force on each other

1a. A car drives around a circular track of diameter 154 m at a constant speed of 45.1 m/s. During the time it takes the car to travel 97 degrees around, what is the magnitude of the car s average acceleration?

b. A car starts from rest, then accelerates at a constant rate over a distance of 63 m. It then immediately decelerates at a constant rate over a distance of 122 m. The entire trip lasts a total duration of 21.7 s. What were the magnitudes of the car s accelerations for the speedup and slowdown stages respectively?

c. A spacecraft starts from rest, and makes a journey to a destination 453000 km from its starting point. It does so by accelerating at a constant rate of 13.64 m/s^2 up to the midpoint of the journey, and then decelerates at the same constant rate of 13.64 m/s^2 for the second half of the journey, ending at rest. How long did the entire journey take?

A lamp is twice as far in front of a plane mirror as a person is. Light from the lamp reaches the person via two paths. It strikes the mirror at a 36.1° angle of incidence and reflects from it before reaching the person. The total time for the light to travel this path includes the time to travel to the mirror and the time to travel from the mirror to the person. The light also travels directly to the person without reflecting. Find the ratio of the total travel time along the reflected path to the travel time along the direct path.

The Sun has an apparent magnitude of -26.74. The closest star system to us, Alpha Centauri, has an apparent magnitude of +0.01 and a luminosity of 1.1519 times that of the Sun. How much brighter is the Sun compared to Alpha Centauri? How close is this star system to us?

Say I rolled a marble down a funnel so that it essentially spiralled into the center and fell through the funnel hole. How would you calculate the number of revolutions around the funnel this marble made before reaching the center of the funnel? I'm using this similarity to find the amount of revolutions an electron would make before it hit the nucleus of a hydrogen, but I can't for the life of me think of a way to calculate number of revolutions of an object traveling in a spiral towards a center.

A horizontal spring with a spring constant of 190 N/cm is compressed 6.3 cm. A wooden block with a mass of 1.5 kg is placed in front of and in contact with the spring. When the spring is released it pushes the block, which slides on a frictionless horizontal surface for some distance. The block then slides up a frictionless incline of 27 above the horizontal and comes to a momentary stop before sliding back down. The system is the spring, the block, the incline, and the Earth. Ignore air resistance. A) Sketch the situation and label all variables for: i. the spring and block before the spring is released ii. the block sliding on the horizontal surface iii. the block sliding up the incline B) List all known quantities. C) Draw the free body diagram for the block sliding up the incline. D) What is the potential energy of the spring before it is released? E) What is the kinetic energy and the speed of the block as it slides on the horizontal surface after the spring has pushed it? F) At what height does the block stop on the incline? G) If the incline were rough, how would the stopping height of the block compare to the stopping height when the incline is frictionless? Explain using energy.

When serving, a tennis player hits the ball horizontally. With a speed of 29.12 m/s. What minimum height, H (in m) from which the ball must be launched to just clear the 0.90 m high net about L = 17.65 m from the server.

How far from the end of the service box (which is a distance of S = 6.80 m from the net) will the ball land if it just clears the net? Use the positive direction if the ball is good (i.e. lands within the service box). Give your answer in meters.

For how long will the ball be in the air? (s)

A 1.9 kg block slides along a horizontal surface with a coefficient of kinetic friction μk = 0.30. The block has a speed v = 1.4 m/s when it strikes a massless spring head-on.

If the spring has force constant k = 120 N/m, how far is the spring compressed?

What minimum value of the coefficient of static friction, μS, will assure that the spring remains compressed at the maximum compressed position?

If μS is less than this, what is the speed of the block when it detaches from the decompressing spring? [Hint: Detachment occurs when the spring reaches its natural length (x=0).]

Explain why the detachment occurs when the spring reaches its natural length (x=0)