physics p3.1

Seite 1

the turning effect

the turning effect is a force called the moment. which can be increased by:

increasing the size of the force

using a longer instrument

the equation for working out the moment is:

moment = force x perpendicular distance pivot (Nm) (N) (m)

centre of mass

"if the mass acts past the base past the base you'll topple"

draw in lines of symmetry to find the center of mass

moments p3.1

balanced moments

this diagram shows a balanced moment

because this is balanced we know that w1 x d1 = w2 x d2

eg. to the left we can calculate w0 if we know w1 d1 and d0. take w1 as 4.0N, d1 as 0.20m and d0 as 0.25m so...

w0 = (w1)(d1) / d0 w0 =(4.0 x 0.20) / 0.25 = 3.2N

circular motion

a hammer throw is a good example of circular motion. for an object moving in a circle at a constant speed at any instant ;

its velocity is directed along a tangent to the circle of direction

the velocity constantly changes direction as it moves around the circle

the change in velocity is towards the center of the circle --------------------------------------------->

therefore the object is constantly accelerating towards the center of the circle and the force acts toward the circle. this force acts towards the resultant force called the centripetal force because it always acts towards the center.

gravitational forces

the force of gravity between any two objects :

is an attractive force

gets better with the mass of each object

gets smaller with greater distance between the two objects