1. Relative and Resultant Velocity Aim: How do we calculate the resultant velocity of an object moving relative to other moving objects? Do Now: You are walking towards the front of a train. If you are walking at 3m/s relative to the train, and the train is moving at 35m/s relative to the ground. What is your speed relative to the ground?

2. 1 Dimensional problems. If you and the object you are on are moving in the same direction, add your velocities. If you and the object you are on are moving in opposite directions, subtract your velocities. 22m/s 7m/s 22m/s 7m/s

3. 1 Dimensional problems. If you are moving in the same direction as the OTHER object, subtract your velocities. If you and the OTHER object are moving in opposite directions, add the velocities. 22m/s 7m/s 22m/s 7m/s

4. Aim: How do we apply relative velocity to 2D problems Do now 1.You are on a cruise boat that is moving at 15m/s relative to the dock. If you are running towards the back of the boat at 6m/s. What is your speed relative to the observer on the dock? 2.During a drag race, you are driving at 75m/s. The other car drives past you as its moving at 81m/s. What is the other cars speed relative to you?

5. 2 Dimensional problems. PERPENDICULAR VECTORS DO NOT AFFECT EACH OTHER! –For example, a motor boat that can move at 7m/s aims West, straight across a 150m wide river that has a current moving at 1.5m/s North. The speed of the boat moving West IS NOT affected by the speed of the current moving North 1.5m/s 7m/s Questions: 1.How long does it take the boat to cross the river? 2.How far up the river does the boat end up? 3.What is the boats relative velocity?

6. - A boat that moves at 11m/s crosses a 350m wide river. If the boat ends up 55m up the river on the opposite bank, how fast is the current in the river? v=? 11m/s 350m

7. -A boat that moves at 6m/s crosses a 750m wide river. If the current in the river is 2.2m/s north, -How far up the river does the boat end up? v=2.2 m/s 6m/s 750m

8. -A boat that moves at 8m/s crosses a 530m wide river with a current that flows at 3m/s at an angle of 60 o from the horizontal. - how long does it take for the boat to cross the river? -How far up the river does the boat end up? 3m/s 8m/s 530m 60 o

9. -A boat that moves at 12m/s crosses a 800m wide river with a current that flows at 2.5m/s at an angle of 20 o from the horizontal. -How far up the river does the boat end up? 2.5m/s 12m/s 800m 20 o

10. Class Work Blue Text Book –Pg 80 # 2,3, 4, 15