QUESTION 1

Engineers wish to launch a satellite from the surface of theMoon. What is the minimum speed the satellite must have to escapethe Moon’s gravity – that is, what is the escape velocity at thesurface of the Moon? The Moon has a mass of 7.3x10^22 kg and aradius of 1.7x10^6 m.

	a.	1700 m/s
	b.	It depends on the mass of the satellite.
	c.	5.7x10^6 m/s
	d.	2400 m/s

10 points   

QUESTION 2

The satellite is guided to a circular orbit about the Sun at thesame distance from the Sun as the Earth (1.5x10^11 m), but far awayfrom the Earth (so only the Sun’s gravity is important). What isthe satellite’s gravitational acceleration due to the Sun, whichhas a mass of 2.0x10^30 kg?

	a.	5.9 mm/s^2
	b.	9.8 m/s^2
	c.	8.9x10^8 m/s^2
	d.	It depends on the mass of the satellite.

10 points   

QUESTION 3

The satellite is guided to a circular orbit about the Sun at thesame distance from the Sun as the Earth (1.5x10^11 m), but far awayfrom the Earth (so only the Sun’s gravity is important). What isthe satellite’s speed?

	a.	5.9 mm/s
	b.	3.0x10^4 m/s
	c.	8.9x10^8 m/s
	d.	It depends on the mass of the satellite.

10 points   

QUESTION 4

The satellite is guided to a circular orbit about the Sun at thesame distance from the Sun as the Earth (1.5x10^11 m), but far awayfrom the Earth (so only the Sun’s gravity is important). What isthe satellite’s gravitational potential energy if it has a mass of200 kg? The Sun has a mass of 2.0x10^30 kg.

	a.	-1.8x10^11 J
	b.	-8.9x10^8 J
	c.	2.9x10^14 J
	d.	-1.2 J

10 points   

QUESTION 5

The satellite is guided to a circular orbit about the Sun at thesame distance from the Sun as the Earth (1.5x10^11 m), but far awayfrom the Earth (so only the Sun’s gravity is important). Thesatellite is the stopped using orbital thrusters and allowed tofall to the Sun. What is the satellite’s speed when it reaches thesurface of the Sun? The Sun has a mass of 2.0x10^30 kg and a radiusof 7.0x10^8 m.

Hint: Use energy conservation. First consider the potentialenergy when it is at the Earth’s orbit, then equate this to the sumof the potential energy at the surface of the sun and the kineticenergy at the surface of the sun.

	a.	It will be going infinitely fast.
	b.	3.8x10^11 m/s
	c.	4.4x10^5 m/s
	d.	6.2x10^5 m/s