Name: ______________________ Class: _________________ Date: _________ ID: A

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HW8 (due 4/3/14)

True/False (2 points each)Indicate whether the statement is true or false.

____ 1. The interior of the Earth is differentiated because it cooled very quickly.

____ 2. The interior of the Earth is hot mainly because of the pressure induced by the weight of the material above it.

____ 3. The center of Earth has approximately the same temperature as the surface of the Sun.

____ 4. The maria, the dark regions of the Moon’s surface, are approximately 1 billion years younger than the rest of its surface.

____ 5. Mars has many large shield volcanoes because it does not have plate tectonics.

Multiple Choice (5 points each)Identify the choice that best completes the statement or answers the question.

____ 1. Which object would have the LOWEST impact on our planet if it were to strike Earth?a. a 1-kg asteroid traveling at 30 km/sb. a 5-kg asteroid traveling at 10 km/sc. a 100-kg comet traveling at 10 km/sd. a 1,000-kg Mini Cooper car traveling at 100 miles/hr, which is 0.05 km/se. a 3,000-kg truck traveling at 35 miles/hr, which is 0.02 km/s

____ 2. Mars, Venus, and Earth are much less heavily cratered than Mercury and the Moon. This is explained by the fact that:a. the rate of cratering in the early Solar System was strongly dependent on locationb. Mars, Venus, and Earth have thicker atmospheresc. Earth and Venus were shielded from impacts by the Moon, and Mars was protected by

the asteroid beltd. Mars, Venus, and Earth were geologically active for a longer period of time than

Mercury and the Moone. Mars, Venus, and Earth are much larger in size than Mercury and the Moon

Name: ______________________ ID: A

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____ 3. Which of the following statements is FALSE?a. The surface of Venus has very few craters primarily because asteroids burn up in its

thick atmosphere.b. Geological features and the chemical composition of some rocks on Mars suggest

liquid water flowed on the surface in the past, but not at the present time.c. Darker regions of the Moon’s surface have less craters and are approximately 1

billion years younger than the lighter regions.d. Volcanoes on Mars are larger, on average, than the Earth’s volcanoes because Mars

does not have moving continental plates.e. Impact craters on the Earth are erased over time because of erosion due to water and

the recycling of its crust.

____ 4. Of the following methods, the age of the Solar System can be determined most accurately by:a. measuring the number of craters per square meter on Mercuryb. radioactive dating of rocks retrieved from the Moonc. carbon dating of rocks from mountains on the Earthd. measurement of the magnetic field variations in rocks under the Earth’s oceanse. measuring the rate of energy production in the Sun

____ 5. If a radioactive element has a half-life of 10,000 years, what fraction of it is left in a rock after 40,000 years?a. 1/2 d. 1/16b. 1/4 e. 1/32c. 1/8

____ 6. Differentiation refers to materials that are separate based on their:a. weight d. densityb. mass e. heat capacityc. volume

____ 7. The observation that the Moon’s average density is similar to the density of the Earth’s _________ supports the collision theory of the Moon’s origin.a. oceans d. atmosphereb. average density e. mantlec. core

____ 8. What is the main reason that the Earth’s interior is liquid today?a. tidal force of the Moon on the Earthb. seismic waves that travel through Earth’s interiorc. decay of radioactive elementsd. convective motions in the mantlee. pressure on the core from Earth’s outer layers.

Name: ______________________ ID: A

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____ 9. What will eventually happen to the Earth when radioactive decays in its interior cease?a. The Earth’s core will solidify. d. The strength of the Earth’s magnetic

field will decrease.b. Continental drift will cease. e. All of the above will happen.c. Earthquakes will cease.

____ 10. Examine the figure below that shows the continental plates of the Earth and the locations of volcanoes and earthquakes. Which statement is FALSE?

a. The Earth’s crust is broken up into 13 separate continental plates.b. Volcanoes occur more often where two plates are coming together rather than

spreading apart.c. Earthquakes happen where two plates come together and when they spread apart.d. The Atlantic Ocean is getting smaller with time.e. Southern California in the United States and Baja in Mexico are sliding northeastward

relative to the rest of the North American Plate.

Short Answer (8 points each)

1. What are the four main processes that shape the surfaces of the terrestrial planets?

2. Give a specific example of a historical impact of an asteroid or comet that hit the Earth. Why are impact craters rare on the surface of Earth but plentiful on the Moon?

3. Three different things can happen when two continental plates meet. What is the name given to each, and briefly explain what happens in each.

4. The American and African/European continents are now separated by the Atlantic Ocean, which is approximately 4,000 km wide. Assuming a continental drift rate of 2 cm/year, how long has it been since they were one land mass?

5. If there is water on Mars today, where is it likely to be? Name two separate pieces of evidence we have that Mars once had flowing water on its surface and how this evidence was obtained.