Question

A boat moves through water at a speed of 15 m/s. While moving at this speed, the drag force on the boat is calculated to be 240 N. What drag force will be present if the speed of the boat is increased to 25m/s

Answer 1

For low speeds, the drag force is proportional to the velocity. So we can write the following proportion:

`15 m/s:240 N = 25 m/s:F`
where F is the drag force in the second situation. By solving the proportion, we find that the drag force at v=25 m/s is

`F= ((240 N)(25 m/s))/(15 m/s)=400 N`