1. Conservation of Momentum

2. Momentum  The velocity and mass of an object give it momentum.  The larger the velocity and mass, the larger the momentum. p = momentum (kgms -1 ) m = mass (kg) v = velocity (ms -1 )  The velocity and mass of an object give it momentum.  The larger the velocity and mass, the larger the momentum. p = momentum (kgms -1 ) m = mass (kg) v = velocity (ms -1 ) p = mv

3. Example 1  What is the momentum of a 50 g tennis ball hit at 80 kmh -1 ?  What is the momentum of an electron moving at 0.1c ?  What is the momentum of a 50 g tennis ball hit at 80 kmh -1 ?  What is the momentum of an electron moving at 0.1c ?

4. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle)

5. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle)

6. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle)

7. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle) momentum transfer

8. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle)

9. Momentum transfer  One object can transfer momentum to another (eg Newton’s Cradle)

10. Conservation of Momentum  Total momentum is conserved in collisions (that is, the initial and final momenta are the same)  The formula above is for a collision between two masses m 1 and m 2.  Total momentum is conserved in collisions (that is, the initial and final momenta are the same)  The formula above is for a collision between two masses m 1 and m 2. p initial = p final m 1 u 1 + m 2 u 2 = m 1 v 1 +m 2 v 2

11. Conservation of momentum in Collisions Applet 1 (two masses) Applet 2 (canon and Carriage)

12. Example 2  A 100 g billiard ball travelling at 3 ms -1 to the right collides with a stationary ball of mass 120 g. The 120g ball moves to the right with a speed of 2 ms -1. What is the final velocity of the 100g ball?