What speed does a motor boat develop after passing 800 m from rest with an acceleration of 4 m / s?

As we know from the school physics curriculum, the distance about uniformly accelerated motion of an object can be calculated using the following formula:

S = (V ^ 2 – V0 ^ 2): 2a, where a is the acceleration, and V and V0 are the final and initial velocities of the object.

In our case, according to the condition of the task, the motor boat starts from the rest state, which means that V0 is equal to 0.

Let’s determine what the final speed will be at the turn of 800 meters, when the acceleration was 4 m / s:

V ^ 2 = 800 * 2 * 4;

V ^ 2 = 6400;

V1 = 80;

V2 = -80 (not suitable).

Answer: 80 m / s.