Physics Experiment

Force & Acceleration

(uses the Pasco interface)

Purpose:

Discussion:

Newton's Second Law, a = Fnet/m or Fnet = ma, relates the net force acting on an object to the object's acceleration. In this lab, you will use a force sensor and an acceleration sensor to explore this relationship experimentally.

Equipment:

Pasco computer interface

dynamics cart

force sensor

acceleration sensor

1.2 m dynamics track

balance

experiment file "f_vs_a"

Setup:
llab setup
This is the setup for the Force vs. Acceleration Lab

  1. Attach the acceleration sensor and force sensor to the dynamics cart as shown. Be sure that the positive direction (marked on the sensor) is the same for both sensors.
  2. Set the "Slow...Fast" switch on the acceleration sensor to "Fast".
  3. Measure and record the mass of the cart + sensors using the balance.
  4. Plug the force sensor into Channel A of the interface, and plug the acceleration sensor into Channel B.
  5. Open the experiment file "f vs. a".


Procedure:
lab screen shot
Screen Shot of the Experiment File

  1. Place the dynamics cart on the track.
  2. Push the "Tare" button on both the force sensor and the acceleration sensor.
  3. Grasp the hook of the force sensor.
  4. Press "Start".
  5. Push and pull the cart back and forth on the dynamics track. As you do so, the computer will measure the force you exert on the cart (in Newtons) and the cart's acceleration (in m/s2)and plot a force vs. acceleration graph.
  6. Press "Stop".
  7. To get the graph to automatically scale itself to the data, press the "Scale to Fit" (scale to fit icon) button.
  8. Take a couple more sets of data. Before you do so, you might want to erase the current data from the graph by un-selecting it in the "Data" menu. Don't delete the data!


Results:

  1. For each data set, select "Linear" from the "Fit" Menu, and the computer will calculate and display the line that best fits your data.
  2. Print each graph, showing the best-fit line.

Analysis:

Things to Notice:

  1. If the force is positive, the acceleration is (positive/negative).
  2. If the force is negative, the acceleration is (positive/negative).
  3. If the force is large, the acceleration is (large/small).
  4. If the force is small, the acceleration is (large/small).

A Little Deeper:

  1. Do the (force, acceleration) data points fall mainly on a straight line, or some other curve? What is the significance of this?
  2. If the (force, acceleration) data points fall more-or-less on a straight line, what is the significance of the slope of this line?

Turn In:

  1. A RERUN-style summary of the lab.
  2. Answers to the analysis questions. Please use sentences.
  3. Printouts of your graphs.
last update March 14, 2002 by JL Stanbrough