Question

A boat is traveling upstream in the positive direction of the x axis at 10 km/h with respect to the water of a river. The water is flowing at 7 km/h with respect to the ground. (a) What is the velocity of the boat with respect to the ground?

Answer 1

Answer:

The velocity of the boat with respect to the ground is 3 km/h

Explanation:

The speed of an object is different depending on the reference system you use. This is called relative speed.

A boat travels upstream, this means that it moves in the opposite direction to the river current.

A boat travels upstream, this means that it moves in the opposite direction to the river current. Then, if the boat moves in the positive direction of the x axis at 10 km / h with respect to the water of a river, the water flows in the negative direction of the x axis at 7 km / h with respect to the ground.

This causes the speed of the boat relative to the ground to be calculated as follows:  

VbG = Vbw - VwG

where VbG is the speed of the boat relative to the ground, Vbw is the speed of the boat relative to the water of the river and VwG is the speed of the water relative to the ground.

So: VbG=10 km/h – 7 km/h

VbG= 3 km/h

The direction of this velocity is in the positive x-direction.