GEOG 2RC3 : physical env't

13.29. The dwarf planet Pluto has an elliptical orbit with a semi- major axis of 5.91 X 1012 m and eccentricity 0.249. (a) Calculate Pluto's orbital period. Express your answer in seconds and in earth years. (b) During Pluto's orbit around the sun, what are its closest and farthest distances from the sun?

An asteroid is in a highly eccentric elliptical orbit around the Sun. The period of the asteroid's orbit is 90 days. Which of the following statements is true about the possibility of a collision between this asteroid and the Earth? 

(a) There is no possible danger of collision.

(b) There is a possibility of a collision.

(c) There is not enough information to determine whether there is a danger of a collision.

1)The earth makes a gravitational force on the moon, and themoon makes a gravitational force on the earth. Which of theseforces is larger?
a)The gravitational force of the earth on the moon isgreater.
b)The gravitational force of the moon on the earth isgreater.
c)The two forces are equal.
d)There is no way to tell.
2) Suppose you could climb a ladder whose height is equal to theradius of the earth. At the top of this ladder
a) your weight would be the same as it is at the surface of theearth.
b)your weight would be ½ its value at the surface of theearth.
c)your weight would be ¼ its value at the surface of theearth.
d) you would be weightless.
3) The moon has potential energy because it is near the earth. Ifit were twice as far from the earth as it is now,
a) its potential energy would be higher than it is now.
b) is potential energy would be less than it is now.
c) its potential energy would be the same as it is now.
4) Suppose a satellite has a circular orbit around the earth. Whydoes it stay in orbit?

a)Because gravity does not act on it in the vacuum of space.
b)Because it is in equilibrium; the inward pull of gravity isbalanced by an outward force.
c) Because as it moves tangentially, the satellite is acceleratedby the force of gravity toward the center of the earth.

5)

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