SPH4U Relative Motion

A boat is travelling upstream at 5 km/h [N] relative to the shore. If there is a current of 7 km/h, what is the boat’s velocity relative to the water? 

• 2 km/h
• 35 km/h
• 12 km/h
• 1.4 km/h

A swimmer jumps into a river and swims straight for the other side at 1.5 km/h[N] relative to the water. There is a current in the river of 2.0 km/h[W]. What is the swimmer’s velocity relative to the shore?

• 2.5 km/h & 37^o N of W
• 3.5 km/h & 53^o N of E
• 3.5 km/h & 74⁰ N of W
• 0.5 km/h & 27^o N/W

•  A conductor in a train travelling at 12.0 km/h [N] relative to the ground while he walks across the aisle at 5.0 km/h [E] relative to the train. What is his velocity relative to the ground? 

• 7 km/h [23^o WofN]
• 1.71 km/h [60^o E of N]
• 60 km/h [89^o E of N]
• 13.0 km/h [23^o E of N]