Force and motion

• forces and motion
• scalars and vectors
• scalar quantities have a size or magnitude (eg. mass and speed)
• vector quantities have a size or magnitude but a specific direction (eg. velocity and acceleration)
• speed (m/s) = change in distance (m)/ time taken (s)
• acceleration is a change in velocity
• acceleration (m/s2) = change in velocity (m/s) / time taken (s)
• a= (v-u) / t
• v= final velocity u= initial velocity
• velocity is speed in a certain direction
• v2- u2= 2 x a x X
• newtons first law
• a body will remain at rest or continue in a straight line if the forces and speed are balanced.
• newtons second law
• when a resultant force acts on a mass then there will be a change in velocity.
• resultant force= an object with different forces acting on it which are +
• weight is the force that a body experiences.
• weight (N) = mass (kg) x gravitational field strength (N/kg)
• mass is the measure of the amount of matter
• Kg
• momentum (kg m/s ) is the energy that keeps a object moving in the same direction
• it is difficult to change the direction of movement of an object with a lot of momentum
• p= m x v
• force is the rate of change of momentum
• force (N) = change in momentum (kg m/s) / time taken for change (m/s)
• newtons third law
• for every action there is a equal and opposite reaction
• stopping distance
• thinking distance= the time taken for a driver to react to a situation
• increases when driver is : tired, distracted, alcohol or drugs
• braking distance= the distance taken to stop once the brakes are applied
• increases if : the roads are icy/wet, worn brakes