# 13/02/20 Momentum Any object that has both mass 13/02/20 Momentum Any object that has both mass and velocity has MOMENTUM. Momentum (symbol p) is simply given by the formula: Momentum = Mass x Velocity (in kgm/s) m/s) (in kg) (in P M V What is the momentum of the following? 1) A 1kg football travelling at 10m/s 2) A 1000kg Ford Capri travelling at 30m/s 3) A 20g pen being thrown across the room at 5m/s

4) A 70kg bungi-jumper falling at 40m/s 13/02/20 Conservation of Momentum In any collision or explosion momentum is conserved (provided that there are no external forces have an effect). Example question: Two cars are racing around Teville Gate. Car A collides with the back of car B and the cars stick together. What speed do they move at after the collision? Speed = 50m/s Mass = 1000kg Speed = 20m/s Mass = 800kg Mass = 1800kg Speed = ??m/s Momentum before = momentum after so 1000 x 50 + 800 x 20 = 1800 x V

V = 36.7m/s More questions 13/02/20 1) A white snooker ball moving at 5m/s strikes a red ball and pots it. Both balls have the same mass. If the white ball continued in the same direction at 2m/s what was the velocity of the red ball? 2) A car of mass 1000kg heading up the M1 at 50m/s collides with a stationary truck of mass 8000kg and sticks to it. What velocity does the wreckage move forward at? 3) A defender running away from a goalkeeper at 5m/s is hit in the back of his head by the goal kick. The ball stops dead and the players speed increases to 5.5m/s. If the ball had a mass of 500g and the player had a mass of 70kg how fast was the ball moving? 4) A gun has a recoil speed of 2m/s when firing. If the gun has a mass of 2kg and the bullet has a mass of 10g what speed does the bullet come out at? (Hint: total momentum before is zero and the gun has a negative velocity afterwards) 13/02/20 A past exam question June 2000

Two lorries are travelling in the same direction along a motorway. Lorry A Lorry B Mass = 20,000kg Mass = 30,000kg Speed = 14m/s Speed = 20m/s 1) Calculate the momentum of Lorry A as it travels along the motorway. 2) Calculate the momentum of Lorry B as it travels along the motorway. (3 marks) 3) Lorry B collides with Lorry A and they stick together. Calculate