a unit with magnitude only.
a physical quantity which has both magnitude and direction.
the moment of a force about any point is defined as the force x perpendicular distance from the line of action of the force to the point.
the law of moments
when an object is in equilibrium, the sum of the clockwise moments is equal to the sum of the anticlockwise moments about a pivot or point.
centre of mass
the point through which a single force on the body has no turning effect.
object returns to equilibrium i.e. obeys principle of moments.
the study of motion with constant acceleration.
the rate of change of displacement with time or v=s/t.
the rate of increase in velocity with time or a=v/t.
area under the line of a speed/time graph.
equations of motion
v = u + at
s = ½(u+v)/t
s = ut + ½ at²
v² = u² + 2as
the maximum speed of an object through a fluid. an object reaches terminal velocity when all the forces acting on it balance out.
Newton's 1st law
every body continues in its state of rest, or uniform motion in a straight line unless external forces act upon it.
Newton's 2nd law
a bodies rate of change of momentum is directly proportional to the force acting on it and takes place in the direction of the force. force=mass x acceleration.
Newton's 3rd law
for every action there is an equal and opposite reaction.
the force which gives a mass of 1kg an acceleration of 1 meter per second.
the amount of matter in an object measured in kg.
the effect of gravity acting on a mass measured in Newton's.
gravitational field strength
is given in size and direction by the force which acts on 1kg placed in the field. on earth it is 9.81 m/s^2 towards the earths centre of mass.