## A fan (not shown) is mounted on a low-friction cart. The thrust of the fan exerts a force directed towards the right (or left) as shown by the arrow. Press “play” to run the animation and plot position, velocity, and acceleration. The thrust in Newtons is indicated. Select Lo Thrust , HI thrust., or Negative thrust. For each value of thrust, adjust the parameters in the boxes below to obtain the best-fit equation for the velocity vs. time.

a=m/sec2   Vo=

##### Acceleration graph below:

Questions:

1. What is the symbolic mathematical equation for velocity vs. time for constant acceleration?

2. What is Newton's 2nd law of motion to calculate the acceleration of a mass if the force and mass are known?

3. From the best linear fit of the velocity graph, obtain the acceleration for each different thrust. Calculate the mass of the cart. The mass should be identical for all "experiments"

End of mid-week assignment. Please e-mail discussions to dcollins@warren-wilson.edu

Physlets written by Wolgang Christian and Mario Belloni of Davidson College.