Download Fields and Forces Gravitational force and fields State Newton`s

1. Fields and Forces
1.1. Gravitational force and fields
1.1.1. State Newton’s universal law of gravitation
Newton’s universal law of gravitational: Every single point mass attracts every other point
mass with a force that is directly proportional to the product of their masses and inversely
proportional to the square of their separation.
𝐹=𝐺
𝑀𝑚
𝑟2
Where:
F= force exerted
G= gravitational field constant
M= mass of object A
m= mass of object B
r= distance between the 2 objects
1.1.2. Define gravitational field strength
Gravitational field: as regions of space where a mass experiences a force
because of its mass.
Gravitational field strength: as the force per unit mass experienced by a small test mass
placed in the field.
𝐹
𝑔=
𝑚
Where:
g= gravitational field strength
F= Force
m= mass
1.1.3. Determine the gravitational field due to one or more point masses
Field lines: are drawn in the direction that a mass would accelerate if placed in the field.
Field strength (g): is given by the density of the lines.
1.1.4. Device an expression for gravitational field strength at the surface of a
planet, assuming that all its mass its mass is concentrated at its centre.
If:
𝐹
𝑔=
𝑚
And:
𝑀𝑚
𝐹=𝐺 2
𝑟
Then:
𝑔𝑚 = 𝐹
Therefore:
𝑀𝑚
𝑔𝑚 = 𝐺 2
𝑟
Therefore:
𝑀
𝑔=𝐺 2
𝑟