Momentum

• Define Momentum:

units:

• State the Law of Conservation of Momentum:

• Describe what this means when momenta are added graphically using vector addition.

• Starting from F=ma , show that Force is equal to the rate of change of momentum (assume the total mass remain constant).

• In a force vs. time graph, what does the area under the graph represent?

• Show that, for an object with momentum p the kinetic energy Ek can be given by Ek=p2

2m(this

only works when the speeds are non-relativistic).

• Even when momentum is conserved, the total kinetic energy of the particles may not be conserved. We can categorize collisions into two types:

• Elastic collisions:

• Inelastic collisions:

• Completely inelastic collisions:

• [Cambridge] Show that the for two objects undergoing an elastic collision, the relative speed of approach is equal to the relative speed of separation:

• For situations involving 2 (or more) dimensions, the momentum is conserved independently in all directions. This means that the total momentum in the horizontal direction before interaction = total momentum in the horizontal direction after interaction and total momentum in the vertical direction before interaction = total momentum in the vertical direction after interaction.

• [Edexcel] Show that for an elastic oblique collision (“glancing blow”) between two objects with the same mass where one object was at rest before collision, the objects move at right angles to each other after collision.