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23 Nov 2019

The moon is observed to have phases in which only a portion of themoon appears to be illuminated. The cycle of phases repeats itselfapproximately every month. Compose a scientific hypothesis toexplain this observation of the moon. Then explain what tests ofyour hypothesis could be made.

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Casey Durgan
Casey DurganLv2
4 Jul 2019
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Related textbook solutions

Physics: Principles with Applications
7th Edition, 2013
Giancoli
ISBN: 9780321625922

Related questions

In 3 of the Appollo lunar experiments astronauts left reflector panels on the moon so that laser beams from the earth could be reflected off the panels and back to earth.Lasers with lamda = 532 nm send pulses of 0.3 J to the moon and the round trip time is measured within delta t = 0.4 ns.In this way, the one way distance to the reflector on the moon is determined regularly within delta l = c*delta t/2 = 6 cm.The beams from the laser have a diameter of 5 km on the moon.(This is the result of the spreading due to diffraction and to athmospherical turbulence).The reflector panels contain 300 mirrors each of diameter 4 cm(a) Find the number of photons sent from the earth in a single pulse(b) find the fraction of these photons that strike anyone of the small mirrors.(c) find the angular divergence delta theta =lamda/d of the reflected beam from this mirror(d = mirror diameter)(d) What is the diameter of the reflected beam when it return to earth?(e)The return light is measured by a photomultipplier at the focus of a telescope.What fraction of the return light is captured by the telescope, whose diameter is 1 m(f) For a single pulse find the total number of photon captured by the the telescope from all all 300 mirrors.This experiment monitors the monn orbit within a few centimeters( compared to the earth-monn distance of 400 million meters) allowing stringent tests of competing theories of gravity.

1. Which of the following describes an object with a non-zero netforce acting on it? Choose all that apply.
The moped accelerated while making a left turn.
The motorcycle traveled at a constant speed while making au-turn.
The truck slowed down while making a right turn.
The spaceship traveled at a constant speed in a straightline.
The car sped up from 50 mph to 65 mph while moving in a straightline.

2. If you observe that an object is accelerating, what should youconclude?
A non-zero net force is acting on it. Only forces causeacceleration. As such, if an object is accelerating it must bebecause a non-zero net force is acting on it.
It must be in free fall.
It must be changing direction. Acceleration is a vector and vectorshave both magnitude and direction. Thus if an object isaccelerating it must be changing direction.
The forces acting on the object must be greater than the forces theobject is exerting.
It must be speeding up. If an object is accelerating that means itis speeding up.

3. Which of the following are true according to Newton's 2nd Law?Choose all that apply.

If the acceleration is zero, then the net force is zero.
If you apply the same force to 2 objects, the one with more masswill have a greater acceleration.
If you apply the same force to 2 objects, the one with less masswill have a greater acceleration.
If two objects have the same acceleration, the one with less masswill have a larger net force exerted on it.
If two objects have the same acceleration, the one with more masswill have a larger net force exerted on it.
The larger the net force on an object is, the larger theacceleration.
The larger the net force on an object is, the smaller theacceleration.

4. A box is on the Moon. The box weighs 152 lb and is in free fall.How much force is the box exerting on the Moon and in whatdirection?

lb
Up
Down
Right
North
East
West
Left
South

5. Which of the following are the correct units for mass? Chooseall that apply.
slugs
u
kg·m/s2
g
N
m/s2
oz
lb

6. If an object is traveling in a circle, which of the followingmust be TRUE? Choose all that apply.
The object is slowing down.
The object is speeding up.
The object has a net force acting on it.
The object has a constant velocity.
The object is accelerating.

) Ion Rocket Engine. A special type of rocket engine useselectricity for propulsion: the ion engine. A soft metal, such ascesium, is vaporized and then electrified (ionized) with highvoltage. These cesium ions are the accelerated by strong electricfields to produce a current of atoms at high velocity. Outside theengine, the ions are then recombined with electrons to restoreelectrical neutrality.

A particular ion engine has an exhaust velocity of 20,000 m/sec.The mass flow (dm/dt) is just 1 milligram per second.

a) What is the thrust produced by this engine?

b) The engine propels a 200 kg spacecraft. What velocity change(delta-v) is achievable by running the engine continuously for onesolid year? (For simplicity, assume a constant mass for the system.One year = 31.56 million seconds.)
---------------------------
) Potential Energy. How much work is required to lift one metricton (1000 kg) of water to an altitude of 1000 meters? (The Sun isdoing this all this time to the Earth’s weather.)
--------------------------------

q) Kinetic Energy 1. A car has a mass of 1200 kg. How much kineticenergy does it have when traveling at a speed of 30 m/sec?

-----------------------
Kinetic Energy 2. The Space Shuttle orbits the Earth at a speed ofsome 7750 meters per second (which is about 260 times that of atypical highway driving speed). With a typical payload, the Shuttlehas a mass of 120,000 kg.

a) What is the kinetic energy of the Shuttle in orbit?
b) The Shuttle reaches orbit in some 500 seconds. At what rate ofwork (power) did the rocket engines perform on the Shuttle to placethe craft and its payload into orbit? Compare this to the maximumpower output of a typical nuclear electric generatingstation.
-----------------------

Solar Power. In space, outside the atmosphere, some 1360 Watts ofradiant power pass through every square meter (at normalincidence).

a) What total amount of power does the Earth intercept from theSun? (The projected area of the Earth is ?RE2, where RE is theradius of the Earth, 6.38 million meters.)

b) Compare this figure to the total amount of power produced by allof human civilization, currently some 40 trillion (1012) Watts.What conclusions about solar power can you draw from thiscomparison?



q














-) Angular Momentum. Assuming a uniform distribution of mass insidethe Earth, calculate:

a) the Earth’s moment of inertia, I;
b) its angular momentum, L = omega(omega=2pi/T) the angularmomentum of the Moon in its orbit around the Earth (L = mvr).Compare these two values. (The sidereal period of the Moon is 27.3days; its mass is 1/81 of that of the Earth; its average orbitalradius is 383,000 km.)

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Q0 Water Pressure. Calculate the value of the water pressure at theChallenger Deep, the deepest known place on the surface of theEarth. The currently accepted depth of the water there is 10,911meters. (This is deep enough to cover Mount Everest, and still havemore than one mile of water above the peak. On January 23, 1960,Swiss explorer Jacques Piccard and US Navy Lieutenant Don Walshbecame the first, and so far, the only people ever to visit thisremote place, descending in the Italian-built bathyscaphTrieste.)



q-8
Mass of Earth’s Atmosphere. The pressure of the Earth’s atmosphereat sea level is 101,300 Pascals (Newtons per square meter.) Thismeans that every square meter of Earth’s surface supports a weightof 101,300 Newtons. From this, determine the mass of Earth’satmosphere. What fraction of the Earth’s total mass is this?





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