Similarities of Translational and Rotational Kinematics
 

•   Measure the angle of the track using the meter-stick.  It is easiest to measure the height H of the track up from the floor at some convenient point along the track, then the length L of the track down to the floor, and then use your knowledge of geometry to calculate the angle φ of the track up from the horizontal.  Enter these values into the table of Question 5.
 
•   Place the cart on the track with the string connected to the mass hanger, with the string running over the largest of the three pulleys on the rotation sensor, and with the translation sensor in position at the bottom of the track.  Place mass on the mass hanger to the nearest 1-g value so that the cart/mass-hanger system is in equilibrium.  Place an extra 20-g mass on the mass hanger so that the cart accelerates up the incline and the hanger comes to rest on the floor. 

•   If the mass balance is free, measure the masses of the cart, m_c, and the masses plus the hanger, m_h, using the mass balance.  Enter the values into the table.  If the mass balance is not free, skip to the next step, then measure the masses afterwards.  

•   Measure the largest pulley’s radius.  Wrap the loop on one end of the meter-long black thread around the post of the position sensor, and run the thread around the circumference of the largest pulley five or six times.  There’s a notch in the side of the pulley that makes it easy to count the number of times that you run the thread around.  After you have an integral number of revolutions, grab the thread as close as you can to the pulley, at both the beginning and end of its travel around the pulley.  Remove the thread, then stretch it out and measure its length along the meter stick to the nearest millimeter.  Record this value of S in the table of Question 5 of your worksheet, as well as the number of times that the thread went around the pulley’s circumference, n.
 
•   Return the cart to the track with the string connected to the mass hanger, with the string running over the largest of the three pulleys on the rotation sensor, and with the translation sensor in position at the bottom of the track.  Zero the two sensors:  the rotational sensor associated with the pulley at the top of the track, and the translational sensor at the bottom of the track.
 
•   Starting with the cart near the top of the incline, practice giving it a push down the incline so that it coasts at least half a meter down before coming momentarily to rest and accelerating back up the incline.  (Be sure to avoid crashes.)