Boats and Streams: Upstream and Downstream Speed Upstream Speed: Imagine a boat as it starts to move away from a dock. The boat's speed as it leaves the...
Upstream Speed:
Imagine a boat as it starts to move away from a dock. The boat's speed as it leaves the dock is called its upstream speed. This refers to the speed at which the boat would travel if it were the only object moving in the water.
Upstream speed can be calculated using the following formula:
Upstream speed = Boat's speed - Water resistance
Boat's speed is the speed of the boat in still water.
Water resistance is the resistance the boat encounters when moving through the water.
Downstream Speed:
When a boat is moving downstream, it is being pushed by the water. This means that the boat's speed as it moves downstream is less than its upstream speed.
Downstream speed = Boat's speed + Water resistance
Example:
A boat travels upstream with a speed of 10 km/h.
The water resistance is 2 km/h.
The downstream speed of the boat will be 12 km/h.
Additional Points:
Upstream and downstream speed are both measured in the same units as the boat's speed.
In still water, the upstream and downstream speeds are equal.
When the water resistance is zero (meaning the boat moves freely), the downstream speed is equal to the upstream speed