gravitation

Question 1

What is a projectile?

Answer 1

A projectile is an object that moves with a constant horizontal velocity whilst simultaneously accelerating vertically due to gravity

Question 2

What is the relationship between the horizontal motion and the vertical motion of a projectile?

Answer 2

they are independent of each other

Question 3

How to satellites go around a star or planet?

Answer 3

they are in freefall

Question 4

What are the horizontal and vertical components of initial velocity?

Answer 4

Horizontal component: uh = u cos θ

Vertical component: uv = u sin θ

Question 5

What is the velocity of a horizontal projectile?

Answer 5

constant

Question 6

What is the velocity of a projectile launched upwards?

Answer 6

non-zero initial vertical velocity

Question 7

What is the acceleration of a vertical projectile?

Answer 7

-9.8ms-1

Question 8

What is gravity?

Answer 8

Gravity is an invisible force of attraction between objects that have mass.
Gravity is a very weak force and therefore is only noticeable when the mass of an object is very big
A Gravitational field is an invisible force field around a mass

Question 9

What is gravity on earth?

Answer 9

The Earths gravitational field strength is 9.8 N kg-1 at sea level.
This means that the Earth attracts each kilogram of mass with a force of 9.8N

Question 10

What is newtons law of gravitation?

Answer 10

F=Gm1m2/r^2
F    = Gravitational force of attraction (N)
G    = Newton’s Gravitational constant 
m1  = mass of object 1  (kg)
m2  = mass of object 2  (kg)
r     = distance between the centre of the 
          2 masses (m)

Question 11

What is the Universal Gravitational constant?

Answer 11

6.67 x10-11 N m2 kg-2