Download Universal Gravitation

Name __________________________________________
AP Physics Summer Work
Universal Gravitation
(1)
The force of gravity is directly proportional to the radial distance between two objects.
A) True
B) False
1) ______
(2)
The value of the universal gravitation constant, G, was discovered by Newton.
A) True
B) False
2) ______
(3)
The universal gravitational constant, G, depends on the distance from the center of earth.
A) True
B) False
3) ______
(4)
The reason the force of gravity controls the motion of planets lies in the fact that the masses 4) ______
involved are very large.
A) True
B) False
(5)
The force of gravity is inversely proportional to the radial distance squared between the two 5) ______
objects.
A) True
B) False
(6)
If one were to halve the distance between the centers of two objects, the force of gravity
between the two objects would be multiplied by four.
A) True
B) False
6) ______
(7)
The force of gravity exerted by the Earth on the Moon is greater than the Moon’s
gravitational force on the Earth.
A) True
B) False
7) ______
(8)
Who was the first scientist to see the connection between falling objects, projectiles and
satellites in orbit?
A) Aristotle
B) Galileo
C) Sir Isaac Newton
D) Copernicus
8) ______
(9)
Why does the Earth exert enough gravitational force on our moon to keep it in orbit
about the Earth when the sun for our solar system is about a million times more massive
than our Earth?
A) The moon is pretty small compared to the Earth.
B) The centripetal force exerted by the Sun is smaller.
C) The Moon has a smaller mass density than the sun.
D) The Moon is closer to Earth.
9) ______
(10)
On Mars’ surface the robot Curiosity will weigh 1260 Newtons. If the radius of Mars is
3400 km, what will Curiosity weigh 6800 km above the surface of Mars?
A) 140 N
B) 315 N
C) 630 N
D) 2520 N
10) ______
Page 2
(11)
By what factor would your weight change if the Earth’s diameter were doubled and its mass 11) ______
were also doubled?
A) You would weigh one-fourth as much.
B) You would weigh twice as much.
C) You would weigh four times as much.
D) You would weigh one-half as much.
(12)
If the gravitational forces of the sun on the planets suddenly disappeared in what kind of
paths would the planets move?
A) The planets would spiral into the sun.
B) The planets would fly off radially outward from the sun.
C) The planets would fly directly toward the sun.
D) The planets would fly off tangentially in straight line paths.
12) ______
(13)
Which requires more fuel: sending a rocket from Earth to the Moon or sending the rocket
form the Moon to the Earth?
A) It takes the same amount of fuel if they travel the same distance each way.
B) It takes more fuel to go from the Earth to the Moon because you have to overcome a
a greater gravitational force.
C) It take more fuel to go from the Moon to the Earth because the Moon is not as massive.
D) It takes more fuel to go from Earth to the Moon because the Earth has an atmosphere
and the Moon does not.
13) ______
(14)
If tides on Earth are caused by gravitational forces when would you expect to see the
highest tides?
A) When the Moon and the Sun are on the same side of the Earth.
B) When the Moon and the Sun are on opposite sides of the Earth.
C) When the Sun and the Moon are at right angles to each other with respect to the Earth.
D) It does not matter at all where the Moon and the Sun are with respect to the Earth
14) ______
(15)
The strength of a gravitational field is sometimes written in terms of force on a single
kilogram of mass. In your Physics classroom the gravitational field strength is 9.8 N/kg.
What would you expect the gravitational field strength to be one Earth radii above the
Earth’s surface?
A) 4.9 N/kg
B) 2.45 N/kg
C) 6.53 N/kg
D) 19.6 N/kg
15) ______
(16)
If a box on the floor has a mass of 46 kilograms then the earth attracts that mass with a
force of
A) 1 Newton
B) 450 Newtons
C) 4500 Newtons
D) You cannot calculate the gravitational force without knowing the mass of the Earth.
16) ______
Page 3
(17)
A really dense planet has the same mass as the Earth but only one-tenth the radius. What
would Haley weigh on this planet if she weighs 400 Newtons on Earth?
A) 4000 Newtons
B) 40 Newtons
C) 4 Newtons
D) 40,000 Newtons
17) ______
(18)
A 20 Newton force existed between two objects. If one object doubled in mass and the
18) ______
other object tripled in mass while the distance between them halved what would be the new
gravitational force between them?
A) 120 Newtons
B) 48 Newtons
C) 60 Newtons
D) 480 Newtons
(19)
If the gravitational field strength at the surface of one planet is 540 Newtons/ kilogram
what would the gravitational field strength be one planet diameter above the planet’s
surface?
A) 270 Newtons/kilogram
B) 180 Newtons/kilogram
C) 60 Newtons/kilogram
D) 90 Newtons/kilogram
19) ______
(20)
The average distance between an electron and a proton in a hydrogen atom is 5.31011 m.
If the rest mass of an electron is given to be 9.111031 kg and the mass of the proton is
given to be 1.671027 kg, what is the gravitational force between the two particles?
(Note the universal gravitational constant, G = 6.671011 Nm2/kg2)
A) 1.011067 Newtons
B) 1.911057 Newtons
C) 3.611047 Newtons
D) 1.521057 Newtons
20) ______
(21)
Calculate the force of gravity between Earth (Mass = 6.0 × 1024 kg) and the Moon (mass
= 7.4 × 1022 kg). The average distance between the Earth and Moon is 3.8 × 108 m.
A) 2.0×1020 N
B) 2.0×1028 N
C) 4.4×1022 N
D) 4.4×1028 N
21) ______
(22)
The mass of an electron is 9.1 × 1031 kg. The mass of a proton is 1.7 × 1027 kg. If the
gravitational force of attraction between an electron and a proton in a hydrogen atom is
1.0 × 1047 N, how far apart are the electron and proton?
A) 1.0×1020 m
B) 1.0×1010 m
C) 1.5×1010 m
D) 1.5×1020 m
22) ______
Page 4
(23)
There is a force on Earth that is directed toward the sun.
A) True
B) False
23) ______
(24)
Because Earth is "falling" around the sun, it will eventually crash into it.
A) True
B) False
24) ______
(25)
The force on a ball decreases as the ball moves farther from Earth.
A) True
B) False
25) ______
(26)
If Earth were its present size but twice as massive, we would weigh less.
A) True
B) False
26) ______
(27)
Because Earth has mass, it also has a gravitational field.
A) True
B) False
27) ______
(28)
Newton had the insight to see that the
A) force on the moon has the same nature as the force on an apple.
B) moon always keeps one side toward Earth.
C) moon is moving.
D) moon orbits Earth.
28) ______
(29)
Newton did not hypothesized that the moon
A) is a projectile.
B) is falling around Earth.
C) has tangential velocity that prevents it from falling into Earth.
D) causes tides on Earth.
29) ______
(30)
Newton reasoned that the gravitational attraction between Earth and the moon must be
A) directly proportional to distance.
B) the same at all distances.
C) reduced by distance.
D) independent of distance.
30) ______
(31)
If the mass of Earth increased, with no change in radius, your weight would
A) decrease.
B) stay the same.
C) increase also.
31) ______
(32)
If the radius of Earth decreased, with no change in mass, your weight would
A) not change.
B) decrease.
C) increase.
32) ______
(33)
A very massive object A and a less massive object B move toward each other under the
of mutual gravitation. Which force, if either is greater?
A) The force on A
B) The force on B
C) Both forces are the same
33) ______