Forces

• when a force moves on an object through a distance, energy is transferred and work is done on the object
• work done(j) = force(N) X distance(m)
• vector


  shows magnitude and direction
• scalar


  shows only magnitude
• moment


  the turning effect of a force
• moment (Nm) = force (N) X perpendicular distance(m)
• the pressure of a fluid means a force is exerted normal to any surface in contact with the fluid
• pressure(Pa) = force(N)/area(m^2)
• calculation for pressure at a certain depth due to column of liquid


  pressure(Pa) = height(m) X density(kg/m^3) X gfs(N/kg)
• stopping distance = thinking distance + braking distance
• atmospheric pressure is created on a surface by air molecules colliding with the surface - as height increases atmospheric pressure decreases as the atmosphere gets less dense
• weight(N) = mass(kg) X gfs(N/kg)
• thinking distance


  how far the car travels during the driver’s reaction time
• braking distance


  distance taken to stop under braking force
• force(N) = spring constant(N/m)X extension(m)
• final velocity(m/s) - initial velocity(m/s) = 2 X acceleration(m/s^2) X distance(m)
• elastic potential energy(j) = 0.5 X spring constant(N/m) X extension^2(m)
• resultant force


  the overall force
• acceleration(m/s^2) = change in velocity/time(s)
• uniform acceleration 


  speeding up at a constant rate
• resultant force(N) = mass(kg) X acceleration(m/s^2)
• friction always acts opposite to the direction of movement, frictional force depends on shape and area
• terminal velocity depends on its drag compared to its weight
• when a force is applied on an object it can bend, compress or stretch