Moments

Moments

1. the turning effect of a force

   • eg a spanner turning a nut or a door handle or a lever( a force multiplier- small force on one side and a bigger forc on the other)

2. m=fxd

   • eg..... 20N x 3.0 m = 60Nm

3. may have to work out missing distance or force

   • 20x 1.5 = 40 x ?
     • 30 = 40x d
       • 30/40 = 0.75

4. Stability

   • if the line of action of the weight lies outside the base
     • there will be a resulting moment and the object will topple
   • Hydraulics
     • liquids are virtually incompressible
       • pressure applied - transmitted equally in all ddirections
     • force multiplier
       • p ( pascals ) = force / area
         • eg 20 x 0.1 = 200 Pa
           • then..... 200 = f / 0.4 ------ so f = 80 N
     • circular motion
       • acceleration = change in velocity / time
       • accelerating towards the centre... resultant force which i scalled centripetal force which acts towards the centre of the circle
         • eg cause of centripetal force could be from the tension of a string or gravity or friction ( eg between skater and ice or tyres and road)
       • an object moving in a circle
         • accelerates towards the centre of the circle ( direction constanlty changes but not the speed)
           • there is a resultant force called centripetal force which causes the accereration
             • centripetal force needed to make an object move in a cirle increases if
               • mass increases
               • speed increases
               • the radius of the circle decreases