PHYS 101, Section W01, Chapter 5 (Homework)
If the weight of an object with mass m is given by W = mg on Earth's surface, what will its weight be inside an airplane at an altitude of 35,000 feet?
It will be slightly less because g is somewhat smaller at that height.
Which of these things has an inverse-square relationship?
the intensity of sunlight and distance from the sun
Your weight on a given planet could be calculated from which of the following?
the mass of that planet and its diameter
What else became calculable when Henry Cavendish calculated the value of G (the gravitational force between two objects on Earth)?
the mass of the Earth
What two facts did Newton need to be able to calculate the acceleration of the Moon?
the distance to the Moon and the time it takes the Moon to make one revolution
What information do scientists use to estimate the total mass of the Milky Way Galaxy?
the fact that all the stars in the galaxy rotate about a common point
What is the gravitational force between two 10 kg iron balls separated by a distance of 0.1 m? How does this compare with the weight of one ball?
.000000667 N W / F(grav) =146926539 N
If you were located halfway between the Earth and the Moon, what acceleration would you have toward Earth? (Ignore the gravitational force of the Moon as it is much less than that of the Earth.)
.011 m/s²
What is the Earth's gravitational force on you when you are standing on the Earth and when you are riding in the Space Shuttle 470 km above the Earth's surface? Answer as a fraction of the surface gravity of Earth. (The Earth's radius is 6400 km.)
.87 x F(earth)
What is the acceleration due to gravity at a distance of three Earth radii above the Earth's surface?
0.61 m/s²
The gravitational force between two very large metal spheres in outer space is 50 N. How large would this force be if the mass of each sphere were halved?
12.5 N
If an astronaut in full gear has a weight of 800 N on Earth, how much will the astronaut weigh on the Moon?
132 N
The planet Mercury has a radius of about 0.38 Earth radii and a mass of only 0.055 Earth masses. Estimate g on Mercury.
3.81 m/s²
Two spacecraft in outer space attract each other with a force of 8 N. What would the attractive force be if they were one-half as far apart?
32 N
An 64 kg satellite orbits a distant planet with a radius of 4700 km and a period of 280 min. From the radius and period, you calculate the satellite's acceleration to be 0.66 m/s2. What is the gravitational force on the satellite?
42.24 N
A solid lead sphere of radius 10 m (about 66 feet across!) has a mass of about 57 million kg. If two of these spheres are floating right next to each other (centers 20 m apart) in deep space, the gravitational attraction between the spheres is only 540 N (about 100 pounds). How large would this gravitational force be if the distance between the centers of the two spheres were tripled?
60 N
Which of these statements is true?
Even at a given distance from Earth's surface, the value of g can vary slightly.
Which of these statements is true about a geosynchronous satellite?
It remains directly above a specific location on Earth's surface.
Which is the BEST description of what causes tides?
Tides are caused by the gravitational pull of the Earth-Moon system.
A gravitational field is all of the following, EXCEPT?
always the same regardless of how the objects move
