OCR AS PHYSICS

DISPLACEMENT

DISPLACEMENT IS THE DISTANCE TRAVELLED IN A PARTICULAR DIRECTION.

VELOCITY

VELOCITY IS DEFINED BY THE EQUATION;

CHANGE IN DISPLACEMENT = VELOCITY MS-2

TIME TAKEN

THE GRADIENT OF A DISPLACEMENT/TIME GRAPH IS EQUAL TO VELOCITY

SCALAR AND VECTOR QUANTITIES

SCALAR QUANTITIE HAVE ONLY MAGNITUDE.

VECTOR QUANTITIES HAVE MAGNITUDE AND DIRECTION.

DISTANCE AND SPEED ARE SCALAR.

DISPLACEMENT AND VELOCITY ARE VECTORS.

ACCELERATION

ACCELERATION IS EQUAL TO THE RATE OF CHANGE IN VELOCITY.

IT IS A VECTOR QUANTITY.

THE GRADIENT OF A VELOCITY/TIME GRAPH IS EQUAL TO ACCELERATION.

THE AREA UNDER THE GRAPH IS EQUAL TO THE DISPLACEMENT.

S.U.V.A.T

V = U+AT

S = (U+V)    X 2

           2

S = UT + 1/2 AT2

V2 = U2 + 2AS

DYNAMICS - EXPLAINING MOTION

NEWTONS 2nd  LAW.

WHAT IS A NEWTON?

MASS...

WEIGHT...

NEWTONS SECOND LAW: NET FORCE f, MASS m AND ACCELERATION, a.

                                               f=ma

A NEWTON IS THE FORCE REQUIRED TO GIVE A MASS OF 1KG AN ACCELERATION OF 1MS IN THE DIRECTION OF THE FORCE.

MASS IS A MEASURE OF AN OBJECTS INERTIA...THE GREATER THE MASS, THE MORE IT RESISTS CHANGE IN MOTION.

WEIGHT OF AN OBJECT IS A RESULT OF THE PULL ON GRAVITY ON IT;

WEIGHT = MASS X ACCELERATION OF FREE FALL. ( W=mg)

               = MASS  X GRAVITATIONAL FIELD STRENGTH

MOMENTS

MOMENT OF A FORCE:

MOMENT = FORCE X PERPENDICULAR DISTANCE OF THE PIVOT THROUGH THE LINE OF ACTION OF THE FORCE.