| what is a projectile | any object that is launched and moves under the influence of gravity |
| what is the path taken by a projectile called | its trajectory |
| what is a satellite | a special type of projectile that follows a circular orbit due to its constant horizontal velocity constant vertical acceleration |
| what is the path followed by a satellite called | its orbit |
| why do satellites have a circular orbit | because they fall towards the earth at the same rate as the earth's surface curves away from it |
| why do astronauts in orbit around the earth experience apparent weightlessness | they are in a constant state of freefall as the spaceship, astronauts and everything inside are all accelerating towards the earth due to gravity. |
| what is gravitational field strength | weight per unit mass in Nkg-1 |
| what is Newtons Law of Universal Gravitation | every object in the universe with a mass attracts every other object with a mass |
| what is the formula for gravitational force of attraction between any two objects | F=G(m1m2)/r^2
F is gravitational force of attraction in Netwons
G is the universal constant of gravitation in metres per kilogram per second squared (m^3kg-1s-2)
m1 is the mass of object 1 iin kg
m2 is the mass of object 2 in kg
r is the distance between the centres of masses in metres |
| why is the formula for newtons law of universal gravitation an inverse square law | because the gravitational force of attraction between two objects varies inversely with the square of the distance between them
(as the distance between the two objects doubles, the force of attraction between them quarters) |
| what type of force is gravitation between two objects | a mutual force between two objects
this means that object 1 will exert a force on object 2 that is equal in magnitude but opposite in direction to the force exterted by object 2 on object 1 |
