Intro to Force and Motion

A) Pulling the cart, take 1

  1. Place the cart on the track.  Make sure the track is fairly level.  Place cart masses in the cart.
  2. Make sure the spring scales are zeroed when horizontal.
  3. Pull the cart while applying a constant 1/2 Newton force with the spring scale.  Observe the motion.
  4. Hook a second spring scale onto the cart (note the magnetic bumpers; steel hooks stick to them), pull so both exert a 1/2 Newton force.  Observe the motion.
  5. Hook the second spring scale onto the cart pulling in the opposite direction.  Pull each scale with the same force.  Try to identify ALL the possible motions that meet this criteria.
  6. Write your observations on the white board to share with rest of class, answering the following questions:
    1. How did the cart move with a constant 1/2 N force?
    2. How did the cart move with two constant 1/2 N forces?  How like and how different from the first case?
    3. How did the cart move with two equal and opposite forces?

B) Investigating Force Sensors

  1. Get out an electronic force sensor, hook it to the USB connector, and that to the computer.
  2. Choose to use data studio, new experiment.
  3. Click on the "Digits display" icon in the lower left panel to get a numerical display.  You may need to drag the right side to make it wider to get additional digits displayed.  (DON'T use full screen mode.)
  4. Zero the electronic force sensor by pressing the "Zero" button on it an releasing.  You should always zero the force sensor before taking a reading.
  5. Hook the force sensor on the spring scale.  Make sure it is zeroed, too.  Press "Start" on Data Studio.
  6. Holding the force sensor steady, pull the spring scale until it reads 1.0 N.  Note the reading on the computer.
  7. Repeater for 2,3,4 and 5 Newtons.
  8. Be prepared to describe the relationship between readings on the sensor and the spring scale.

C) Pulling the cart, take 2

  1. Download the DataStudio file ForceAndMotion.ds and open it in DataStudio.
  2. Mount the force sensor on the cart by placing it on top at the magnetic bumper side, and threading the screw through the hole on the sensor labeled "Cart," then tighten it until the sensor is securely mounted on the cart.
  3. Place the cart on the track and the cart masses in the other part.
  4. Place the motion detector at the end of the track away from the hook on the force sensor.
  5. Grasp the hook on the force sensor then press the "Start" button on DataStudio.
  6. Move the cart back and forth on the track several time by the hook on the motion sensor.
  7. If need be, adjust the scale on the force, velocity and acceleration graphs so that the data is about full screen.
  8. Sketch the general shape of the force, velocity and acceleration graphs on the white board.  Does the force graph have more of the shape of the acceleration or the velocity?