Newton’s Universal Law of Gravity
Every object attracts every other object with a
force that is directly proportional to the masses of
the objects and inversely proportional to the
square of the distance between the centers of the
objects.
Gravitational Force (N)
M1 and M2 = 10 kg
8E-11
7E-11
6E-11
5E-11
4E-11
3E-11
2E-11
1E-11
0
0
20
40
60
Distance (m)
80
100
𝑚1 𝑚2
𝐹𝐺 = 𝐺
2
𝑟
G = Universal Gravitational Constant 6.67E-11 Nkg-2m2
m1 = mass 1 (kg)
m2 = mass 2 (kg)
r = distance between the centers (m)
F1 = F 2
As shown in the diagram below, the force acting on two masses separated by a
distance d is 40 N. Calculate the force for each of the following changes:
m1
40N
40N
m2
r
The distance between the masses is doubled.
Mass 1 is doubled.
The distance between the masses is halved and both masses are doubled.
The distance is doubled and both the masses are doubled.
Use Newton’s Universal Law of Gravity to solve for the unknown
quantity in each row of the table shown below
Force
Mass 1
Mass 2
distance
40 kg
70 kg
2m
6.0 x 10^24 kg
7.4 x 10^22 kg
3.8 x 10^8 m
600 N
6.0 x 10^24 kg
60 kg
3 x 10^-7 kg
200 kg
5m
The mass of the Earth is 6.0E24kg and its radius is 6.4E6
meters. Find the gravitational force on a 60kg man standing on
the Earth.
What would the gravitational force be on him in the
international space station which is orbiting at a height of
430km above the Earth’s surface? What would his mass be?