Conceptual Physics

1.2 A neutron star and a black hole are 3.34e+12 m from each other at a certain point in their orbit. The neutron star has a mass

of 2.78×10^30 kg and the black hole has a mass of 9.94×10^30 kg. What is the magnitude of the gravitational attraction between

the two?

N

1.3 An asteroid orbiting the Sun has a mass of 4.00×10^16 kg. At a particular instant, it experiences a gravitational force of

3.14×10^13 N from the Sun. The mass of the Sun is 1.99×10^30 kg. How far is the asteroid from the Sun?

m

1.4 The gravitational pull of the Moon is partially responsible for the tides of the sea. The Moon pulls on you, too, so if you are on

a diet it is better to weigh yourself when this heavenly body is directly overhead! If you have a mass of 85.0 kg, how much

less do you weigh if you factor in the force exerted by the Moon when it is directly overhead (compared to when it is just rising

or setting)? Use the values 7.35×10^22 kg for the mass of the moon, and 3.76×10^8 m for its distance above the surface of the

Earth. (For comparison, the difference in your weight would be about the weight of a small candy wrapper. And speaking of

candy...)

N

1.5 Three 8.00 kg spheres are located on three corners of a square. Mass A is at (0, 1.7) meters, mass B is at (1.7, 1.7) meters,

and mass C is at (1.7, 0) meters. Calculate the net gravitational force on A due to the other two spheres. Give the

components of the force.

( , ) N

Section 2 - G and g

2.1 The top of Mt. Everest is 8850 m above sea level. Assume that sea level is at the average Earth radius of 6.38×10^6 m. What

is the magnitude of the gravitational acceleration at the top of Mt. Everest? The mass of the Earth is 5.97×10^24 kg.

m/s^2

2.2 Geosynchronous satellites orbit the Earth at an altitude of about 3.58×10^7 m. Given that the Earth's radius is 6.38×10^6 m and

its mass is 5.97×10^24 kg, what is the magnitude of the gravitational acceleration at the altitude of one of these satellites?

m/s^2

2.3 Jupiter's mass is 1.90×10^27 kg. Find the acceleration due to gravity at the surface of Jupiter, a distance of 7.15×10^7 m from its
center.
m/s^2

2.4 A planetoid has a mass of 2.83e+21 kg and a radius of 7.00×10^5 m. Find the magnitude of the gravitational acceleration at
the planetoid's surface.
m/s^2

Section 8 - Interactive problem: Newton’s cannon

8.1 Use the simulation in the interactive problem in this section to determine the initial speed required to put the cannonball into

circular orbit.

m/s

Section 9 - Circular orbits

9.1 The International Space Station orbits the Earth at an average altitude of 362 km. Assume that its orbit is circular, and

calculate its orbital speed. The Earth's mass is 5.97×10^24 kg and its radius is 6.38×10^6 m.

m/s

9.2 An asteroid orbits the Sun at a constant distance of 4.44e+11 meters. The Sun's mass is 1.99×10^30 kg. What is the orbital

speed of the asteroid?

m/s

9.3 The Moon's orbit is roughly circular with an orbital radius of 3.84×10^8 m. The Moon's mass is 7.35×10^22 kg and the Earth's

mass is 5.97×10^24 kg. Calculate the Moon's orbital speed.

m/s

9.4 The orbital speed of the moon Ganymede around Jupiter is 1.09×10^4 m/s. What is its orbital radius? Assume the orbit is

circular. Jupiter's mass is 1.90×10^27 kg.

m

Copyright 2007 Kinetic Books Co. Chapter 12 Problems^243