1. Now you've covered momentum lets look again at last weeks question. Tarzan is running towards a cliff, ready to swing down, rescue Jane from some poisonous snakes, and make it back up to a tree on the other side. Now we must remember that energy isn't conserved in the collision (of course it is, but some of the energy is lost as heat, sound, etc... so its not recoverable), but momentum is!

If the height of the cliff is 10 m, the height of the tree on which Tarzan hopes to land is 7 m, the mass of Tarzan is 100 kg and the mass of Jane is 50 kg. What velocity does Tarzan have to be running at to rescue Jane?

2. You are in a small boat in a swimming pool and have a brick also in the boat with you. You throw the brick overboard and into the swimming pool. Does the level of the water in the swimming pool rise, stay the same or decrease? Show calculations to back up your answer!

3. In the olden days we used to have milk in bottles delivered by the milkman. The cream would rise to the top of the bottom, and occasionally a bird would come along and peck at the top of the bottle to get at the cream! Compare the milk bottle where the cream is still uniformly mixed with the milk, to the same milk bottle later on when the cream has separated and risen to the top. Does the hydrostatic pressure at the bottom of the milk bottle remain the same during the phase separation of the cream?