# Calculating Thrust and Resistance

sammycs

## Homework Statement

i built a boat for physics class with an electric motor. we are asked to calculate the thrust of the motor and the resistance of the hull using Newton's second law of motion. i conducted an experiment (to collect data in order to find resistance) that required a string attached to the front of the boat in a trough of water (which was placed up off the ground) with the motor turned off. the string had a 20g mass on the end of it. when we let the mass fall to the ground, it took 2.35s to fall .88m. i conducted another experiment (to collect data in order to measure thrust) and tied the string to the back end of the boat with the motor turned on. there was a 20g mass tied on the end of the string again. we measured a .1m length in the trough and found out that the boat moved .1m backwards in 1.33s. Key information: the boat has a mass of .154Kg

## Homework Equations

d= Vi X t + 1/2 A t(squared)
Fg= mg
F=ma
F = Fapplied + Ffriction??????
probably others but im unsure

## The Attempt at a Solution

FIRST EXPERIMENT TO FIND RESISTANCE
calculated the force of gravity acting upon the mass ---> .196N
calculated the acceleration of the mass falling .88m in 2.35s ---> .32m/s(squared)

SECOND EXPERIMENT TO FIND THRUST
calculated the force of gravity acting upon the mass ---> .196N
calculated the acceleration of the mass falling .1m in 1.33s --->.113m/s(squared)

WHAT SHOULD MY NEXT STEPS BE? thanks so much