# Finding the fianl Velocity

wermichiel

## Homework Statement

The model is a car with weights dropping from certain height and propels the car forwards. (Some GPE converted to KE knowledge involved.) And the question is to find a theoretic maximum velocity (final velocity) as the mass of car/weight and the height of weights are constant. All the frictions are not taking in consideration. We know the distance(s) and the time (t), also the M (mass of weights) and the H(height of weights).

## Homework Equations

What I did is to measure the running time of car and the distance the car traveled within this time. Therefore, the work has done is completely equal to the kinetic energy. W=KE=GPE=mgh. (Due to the formula W=Fd, the force can be calculated. Then F=ma, acceleration of car has worked out. Finally the V, by Vt=V0+at, is calculated.

## The Attempt at a Solution

My question is that is this the easiest way to solve it? Is there any other method that can work without thinking so many procedures?

Homework Helper
Welcome to PF!

Hi wermichiel! Welcome to PF!
… (Due to the formula W=Fd, the force can be calculated. Then F=ma, acceleration of car has worked out. Finally the V, by Vt=V0+at, is calculated.

My question is that is this the easiest way to solve it? Is there any other method that can work without thinking so many procedures?

Yes!

Your formula W = Fd (for the work done) doesn't really work in this case (what is d?).

As you say, KE = GPE= mgh,

so just use KE = 1/2 mv2.

wermichiel