Newton's Second Law

LPC PhysicsNewton’s Second LawRevised 12/08The quantity m2+ m 3will remain constant—you will vary the force applied to the systemby incrementally moving masses off of the air carriage and onto the end of the string.The force applied to the system is given by = m g . The acceleration is therefore:F3Fm g m ga = 33==m + m + m m + m + m m. Eq. 1123123Experiment:1. Level the air track, using the carriage or a carpenter’s level.2. Using the rubbing alcohol and tissues provided, clean the air track and carts.3. Measure the mass of the air carriage and attach a long string to it.4. Screw a smart pulley into the photogate. Clamp the smart pulley with photogate to theend of the table. Run the string across the pulley and adjust the height of the pulleyso that when the air carriage is on the track, the string is horizontal.5. In addition to the air carriage, you will use a total mass of 200g ( m2 + m3= 200g)To start, attach 30g to the end of the string and place 170g on top of the air carriage( m = 170g , m = 30g2 3). Adjust the length of the string so that the hooked massdoes not hit the ground before the cart reaches the end of the track.6. Set up the Lab Pro by plugging in the AC Adaptor and connecting to the computerwith a USB cable. Connect the photogate to the Lab Pro using a cable that has oneblack end and one white end. Make sure that the tiny slider on the inside of thephotogate is not obstructing the light beam.7. Open the file newtons_second.cmbl (or .xmbl) from the Experiments folder on thedesktop.8. Check to be sure that the photogate is working by passing your hand through thebeam. A red LED should light when the gate is blocked, and its status (located underthe Logger Pro toolbar) should change from “unblocked” to “blocked”.9. If everything seems good, get the cart set on the air track, turn on the air supply, clickthe Collect button, and release the cart. You should see data appearing in the datatable.10. Repeat this measurement 10 times. Each time, use the slope of the velocity vs. timegraph to determine the acceleration.2 of 3