Title:  Riding the Elevator with Isaac Newton
Obj: Determine the acceleration of an elevator using ΔForce
Materials: Elevator, force sensor with Xplorer7, ring stand with bar, 1 kg mass, DataStudio7 on computer, bathroom scale

Procedure
1.  Sketch the free body diagrams (FBD) of the elevator initially accelerating down, at constant down velocity, stopping at the bottom, accelerating up, stopping at the top (total of 5 FBD).
2.  Take the Xplorer7 apparatus to the elevator, placing the stand on the floor of the elevator.  Have one or two students also stand on a bathroom scale and observe changes in Aweight.@
3.  Turn on Xplorer7,  then press the zero button on the force sensor to set the 1 kg mass to a value of zero Newtons.  (You may not get exactly zero even after several tries, so simply continue with the next step.)
4.  When ready, push the elevator G button to go down, then immediately as the door is closing press the large ' button on the Xplorer7 to start recording force.
5.  When the elevator stops on the G floor, press the ' button again to stop recording. This is the data set called ARun One.@
6.  Repeat Steps 3-5, except push the elevator 2 button for the upward return trip.  This is ARun Two.@

Analysis
1.  Retrieve your two data sets from Xplorer7 onto the computer as described by the physics teacher.
2.  Find the AData@ icon, then select Run One, then Run Two, each time printing the graph (hit Ctrl P).
3.  For Run One, find the maximum negative force.  This is the weight Alost@ by the 1 Kg mass while accelerating downward.  Determine the acceleration of the elevator using Newton=s 2nd Law.
4.  Repeat Step 3 for the stop at the Ground Floor. (There may be two force maximums; choose the 1st one.
5.  Repeat acceleration calculations for the up ride.
6.  Where did you feel Alighter?@   AHeavier?@  Explain in terms of the elevators normal force.
7.  Is the ride on the elevator a Asmooth@ one?  What evidence on you graph indicates otherwise?
8.  Describe how Newton=s 1st and 3rd laws relate to an elevator ride?  Be specific because this is your summary.

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