1. Relative Velocity The velocity of an object is relative to the observer who is making the measurement.

2. Ex The engine of a boat drives it across a river that is 1800 m wide. The velocity vBW of the boat relative to the water is 4.0 m/s, directed perpendicular to the current. The velocity vWS of the water relative to the shore is 2.0 m/s. (a) What is the velocity vBS of the boat relative to the shore? (b) How long does it take for the boat to cross the river?

3. Ex Two cars approach an intersection along perpendicular roads with the following velocities: vAG = velocity of car A relative to the ground = 25.0 m/s, eastward vBG = velocity of car B relative to the ground = 15.8 m/s, northward Find vAB, where: vAB = velocity of car A as measured by a passenger in car B.