8. One radian equals approximately Your answer 9. If a 14 kg box is raised to a height of 4.0 m on Earth, what is its gravitational potential energy relative to the ground? Your answer

C7 9.) If the orbit is elliptical, rather than circular, what can be said about the work done by the Sun on Earth? a.) It does not matter whether the orbit is circular or elliptical, no work is done. b.) The work the Sun does on Earth causes the tides.    c.) Whether the orbit is circular or elliptical, work must be done to propel Earth around the Sun. d.) If the orbit is elliptical, work is done to speed up or to slow down Earth, depending on its location in orbit. e.) The work the Sun does on Earth accounts for Earth's changes of season.

A 1,060 kg meteor strikes the surface of the Moon. What is the work done (in J) on the meteor by the gravitational field of the Moon, if we assume the meteor comes from deep space? The work done by the Moon's gravitational field is equal to the negative of the change of potential energy of the meteor-Moon system. You can assume the meteor comes from infinitely far. What is the final distance of the meteor, if it lands on the Moon's surface? You will need to look up two physical characteristics of the Moon to solve this problem. J

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2. For a satellite in a circular orbit around the earth, the gravitational force from the earth on the satellite causes the centripetal acceleration. The amount of work done by the gravitational force from the earth on the satellite A) is zero B) is greater than zero. C) is less than zero. D) would be different if the masses of the earth and satellite were different. E) can't be determined without a calculator and some data. i. Prove your answer for #2 by using the formula for work, W: (Hint: Consider just a short segment of the orbit, rather than the full orbit. Draw and label on the diagram above to support your work.) ii. Prove your answer for #2 by talking about the satellite's kinetic energy, AKE: (Do not use your work from part i to answer part ii–give a separate proof in part ii.)

A 70 kg secret agent skis down a hill and grabs a 200 kg bag then flies off a 12 m high cliff. The hill can be considered a 1/4 of a circle with a radius of 20 m. a) The initial mechanical energy of the agent at the top of the hill is 14,560 J relative to the location of the bag. If the average force of friction is 120 N determine the velocity of the agent before he picks up the bag. B) what is his apparent weight right before he picks up the bag? C) how fast is the agent traveling after he grabs a bag? D) how far from the base of the cliff does the agent land? Assume the resistance is negligible. E) Assume that the agent in his bag come to rest upon colliding with the ground at the base of the cliff. What is an impulse that he in the bag experiences? Estimate the resulting contact force on the agent. Discuss the likelihood of his living through the collision.

1. The Hubble space telescope orbits the Earth at an altitude of approxi- mately 600 kilometers and has a mass of 1.11 × 104 kg. (a) be pulled down to the surface of the Earth. Ignoring all air resistance, determine the speed with which the telescope would impact the Earth. Use mgh as the gravitational potential energy, where m is the mass of the telescope, g = 9.81 m/s? (the acceleration due to gravity at the surface of the Earth), and h is the distance the Hubble space telescope were to come to an abrupt stop it would above the surface of the Earth. (b) gravitational potential energy, Ug = -GmM/r, where G is Newton's gravitational constant, m is the mass of the telescope, M is the mass of the Earth, and r is the distance from the center of the Earth to the Hubble telescope. Repeat the calculation from Part (a) using the actual expression for the