Elevator Motion Lab

by Mary Norris, Virginia Tech mnorris@vt.edu

Purpose

To investigate forces, Newton's 2nd and 3rd laws, and free body diagrams

Procedure
1. Draw a free-body diagram for a person standing on a scale in the elevator:  a)  at rest; b) accelerating upward; c) accelerating downward; d) moving at a constant velocity upward or downward.

2. Fill in the first two columns (your hypothesis).

3. Write the scale readings in pounds in the table when we ride the elevator.  Convert these to Newtons (1 lb=4.45 N).

4. Record the persons’s weight on your free-body diagram.

5. Compute the net force for each part of the elevator ride.

6. Compute the person’s mass.  Remember that weight in Newtons is mass in kg times 9.8!

7. Find the person’s acceleration.  (Use F=ma.)

8. Write a few sentences that answer the following:  If you wake up in an elevator and there are no windows or lights, can you tell if you are moving or not?  How?

Data

 Data table Elevator Motion Hypothesis Direction of Fnet and anet (up, down, zero) Scale Reading(N) (This is the normal force!) Scale Reading (more, less, weight) Fnet (N) anet m/s2 1.  At Rest Going Down 2.  Speeding up at top Going Down 3.  Constant speed downward Going Down 4.  Slowing down at bottom Going Up 5.  Speed up at bottom Going Up 6.  Constant speed upward Going Up 7.  Slow down at top 8.  Cable Breaks A special thanks to VASTfor hosting our web site.