# Finding net force

1. Feb 12, 2009

### hatcheezy

An airboat with mass 4.38 102 kg, including passengers, has an engine that produces a net horizontal force of 8.08 102 N, after accounting for forces of resistance. a>how long does it take the airboat to reach a speed of 16.0 m/s? b>After reaching this speed, the pilot turns off the engine and drifts to a stop over a distance of 50.0 meters. Find the resistance force, assuming it's constant.

acceleration i found to be 1.84 m/s^2

a = 8.70 s
b = -1120 N

c> Suppose the pilot, starting again from rest, opens the throttle only partway. At a constant acceleration, the airboat then covers a distance of 64.0 meters in 11.5 seconds. Find the net force acting on the boat.

i need help finding c.....i would appreciate steps in finding the solution-notjust the answer.

2. Feb 12, 2009

### quantize

use DeltaX = Vot + 1/2 at^2

remember he is starting from rest (Vo = 0, so the term drops)

solve for a(acceleration)

then multiply acceleration by the mass to get the net force from Newton's Second Law.