Doubling the resultant force doubles the acceleration Force , mass and acceleration a = 2 m/s/s 2 N 1 Kg Doubling the resultant force doubles the acceleration Acceleration  Resultant Force a  F or F = ma

a = 30 m/s/s 1200Kg F = ma F = 1200 x 30 F = 36000 N

Use Force = mass x acceleration to calculate the resultant force on these objects : Use acceleration = resultant force mass to calculate the acceleration of these objects : Q1 Q5 A ball of mass 2Kg accelerates at 3 m/s/s 20Kg 2 x 3 = 6 N 40 / 20 = 2 m/s/s Q2 A truck of mass 2000Kg accelerates at 2 m/s/s Q6 2000 N 3000 N 2000 x 2 = 4000 N 2000 Kg 1000 / 2000 = 0.5 m/s/s Q3 A helicopter of mass 3000Kg accelerates at 4 m/s/s Q7 3000 x 4 = 12000 N 2Kg Q4 A rugby ball of mass 2Kg accelerates at 5 m/s/s 2 x 5 = 10 N 8 / 2 = 4 m/s/s

Force, mass and acceleration A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? ........................... m/s/s A force of 3000N acts on a car to make it accelerate by 1.5m/s2. What is the mass of the car? ……………….Kg 3) A car accelerates at a rate of 5m/s2. If its mass is 500kg how much driving force is the engine applying? ………………N 4) A force of 10,000N is applied to a boat of mass 20,000kg mass. How much does it accelerate by? ………………………m/s2 F A M

Force, mass and acceleration A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? ........................... m/s/s A force of 3000N acts on a car to make it accelerate by 1.5m/s2. What is the mass of the car? ……………….Kg 3) A car accelerates at a rate of 5m/s2. If its mass is 500kg how much driving force is the engine applying? ………………N 4) A force of 10,000N is applied to a boat of mass 20,000kg mass. How much does it accelerate by? ………………………m/s2 Q1 F = m a F = a m 1000 = a 500 2 m/s2 = a F A M

Force, mass and acceleration A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? ........................... m/s/s A force of 3000N acts on a car to make it accelerate by 1.5m/s2. What is the mass of the car? ……………….Kg 3) A car accelerates at a rate of 5m/s2. If its mass is 500kg how much driving force is the engine applying? ………………N 4) A force of 10,000N is applied to a boat of mass 20,000kg mass. How much does it accelerate by? ………………………m/s2 Q2 F = m a F = m a 3000 = m 1.5 2000 Kg = m F A M

Force, mass and acceleration A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? ........................... m/s/s A force of 3000N acts on a car to make it accelerate by 1.5m/s2. What is the mass of the car? ……………….Kg 3) A car accelerates at a rate of 5m/s2. If its mass is 500kg how much driving force is the engine applying? ………………N 4) A force of 10,000N is applied to a boat of mass 20,000kg mass. How much does it accelerate by? ………………………m/s2 Q3 F = m a F = m a F = 500 x 5 F = 2500 N F A M

Force, mass and acceleration A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? ........................... m/s/s A force of 3000N acts on a car to make it accelerate by 1.5m/s2. What is the mass of the car? ……………….Kg 3) A car accelerates at a rate of 5m/s2. If its mass is 500kg how much driving force is the engine applying? ………………N 4) A force of 10,000N is applied to a boat of mass 20,000kg mass. How much does it accelerate by? ………………………m/s2 Q4 F = m a F = a m 10000 = a 20000 0.5 m/s2 = a F A M

Experiment to investigate how force effects acceleration Interrupt card to compute acceleration Light gate connected to computer 1N 1 Kg The force caused by gravity on 100g mass is = 1N Assume there is no friction today!

Acceleration ( m/s/s ) Force ( N ) Acceleration ( m/s/s ) 1 0.5 2 1.0 2.5 1.5 3 2.0 4 2.0 5 1.5 2.5 1.0 0.5 1 2 3 4 5 Force ( N )

For constant mass Conclusions: Acceleration ( m/s/s ) Force ( N ) 1 0.5 2 1.0 2.5 1.5 3 2.0 4 2.0 5 1.5 2.5 1.0 0.5 Conclusions: 1 2 3 4 5 Force ( N )

* the acceleration nearly increases in direct proportion to the force ( m/s/s ) Force ( N ) Acceleration ( m/s/s ) For constant mass 1 0.5 2 1.0 2.5 1.5 3 2.0 4 2.0 5 1.5 2.5 1.0 0.5 Conclusions: * the acceleration nearly increases in direct proportion to the force ( if the force doubles so does the acceleration ) 1 2 3 4 5 Force ( N ) Why nearly?

* the 1/acceleration increases in direct proportion to the mass ( s2/m ) Mass ( Kg ) Acceleration ( m/s/s ) 1/acceln ( s2/m ) For constant force 1 4.0 0.25 2 2.0 0.50 2.00 3 1.5 0.75 1.00 4 1.0 1.0 5 0.5 2.0 0.75 0.50 Conclusions: * the 1/acceleration increases in direct proportion to the mass ( if the mass doubles the acceleration halves, and 1/acceln increases in direct proportion. 0.25 1 2 3 4 5 Mass ( kg)

Acceleration ( m/s/s ) Force ( N ) Acceleration ( m/s/s ) 1 0.5 2 1.0 2.5 1.5 3 2.0 4 2.0 5 1.5 2.5 1.0 Conclusions: ............................................................. 0.5 1 2 3 4 5 Force ( N )

1/ acceleration ( s2/m ) Mass ( Kg ) Acceleration ( m/s/s ) 1/acceln ( s2/m ) 1 4.0 0.25 2 2.0 0.50 2.00 3 1.5 0.75 1.00 4 1.0 1.0 5 0.5 2.0 0.75 0.50 Conclusions: ............................................................. 0.25 1 2 3 4 5 Mass ( kg)