Question 4. You are driving your car at 45 mph. Your car has mass1435kg. You run into a car that has mass 1084kg and is going 55 mphin the opposite direction. The two cars lock bumpers, so they movetogether. No one hits the brakes. How fast will the cars move afterthe collision? Give your answer in mph to two decimal places.

Correct answer: 1.97

Question 5 (1 point)
If your distance from the center of a planet becomes 0.81 timeswhat it was before, what happens to your weight? Give the answer interms of the number by which you would multiply your originalweight. Express your answer in scientific notation, to threesignificant figures. E.g. if you move to 3.4 times as far from thecenter of the planet as you were before, your weight would bemultiplied by (1/3.4 squared) = 0.08650519=8.65E-2. This answer hasNO units

Correct answer: 1.52E0 (1.52 * 100)

Question 6 (1 point)
If you weigh 232.12 lb on the Earth, what do you weigh at the topof a tower (on Earth) where the tower is 0.22 Earth radii tall.Give your answer in pounds to two decimal places.

Correct answer: 155.95

Question 7 (1 point)
If you weigh 96.6 lb on the Earth. Then the Earth collapses. Thereis no change of Earth's total mass, and the surface just contracts,but the radius decreases to 0.15 times what it was formally? Whatdo you weigh after the expansion. Tell the number of pounds to twodecimal places.

Correct answer: 4293.33

Question 8 (1 point)
If you weigh 142.2 lb on the Earth, what do you weigh on adifferent planet where the planet has mass 1.0 times as much asEarth's and radius 0.5 times as large as Earth's. Give your answerin pounds to two decimal places.

Correct answer: 568.80

Question 9 (1 point)
What is the smallest velocity that will enable you to escape fromthe Earth if you are 2.66 Earth radii from the center of the Earth?Give your answer in scientific notation to three significantfigures. Remember that the Earth orbits the Sun at 30 km/sec andthat satellites at about 1 Earth radius from the center go 7.8km/sec.

Correct answer: 6.76E0 (6.76 * 100)

Question 10 (1 point)
You hit the 8 ball and it moves East at 3.8 cm/sec. It hits the 3ball. After the collision, the 8 ball continues to move, but withspeed 2.3 in the East direction. How fast does the 3 ball move?Tell the answer to one decimal place and follow it by the directionthat it moves.

Correct answer: 1.5

Question 11 (1 point)
A rocket has 556 kg of fuel and 142 kg of solid parts. The fuelexits the rocket at a speed of 4504 meters/second. If the fuelcomes out all at one moment, how fast will the rocket be goingafter the fuel leaves? Assume that the rocket and the fuel were notmoving before the fuel left. Use the positive sign for thedirection that the fuel goes. Express your answer in scientificnotation to three significant figures.

Correct answer: -1.76E4 (-1.76 * 104)

) 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 Earthâs 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 Earthâs 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.)

------------------------------------

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 Earthâs Atmosphere. The pressure of the Earthâs atmosphereat sea level is 101,300 Pascals (Newtons per square meter.) Thismeans that every square meter of Earthâs surface supports a weightof 101,300 Newtons. From this, determine the mass of Earthâsatmosphere. What fraction of the Earthâs total mass is this?

Weekly leaderboard

Home

Homework Help 3,900,000

Physics 110,000

Unlock all answers

Related textbook solutions

Physics: Principles with Applications

Related questions

Weekly leaderboard