In this experiment a trolley is allowed to roll down a runway which is tilted at an angle. The runway must first be tilted to overcome the friction in the wheels of the trolley. A ticker tape timer is used to measure the velocity near the start of its journey (u) and near the end(v). The acceleration can then be calculated.
Note: In this simulation the angle of the runway can be changed by dragging the slider right or left.
Using the slider below the simulation, raise the runway a few degrees.
Press "Release Trolley". If the trolley does not move raise the runway a little more and try "Release Trolley" again. When friction is overcome the trolley accelerates very slowly. In the lab, at a slightly lower angle, a little push would make it move with constant velocity.
Press "Get Tape and Ruler".
Measure and record a five-space distance (5/50 s) near the start
Calculate "u" = distance/0.1. Calculate "v" in a similar way near the end of the tape
Calculate the acceleration using the formula a = (v - u) / t where t is the number of dots from start of u interval to start of v interval / 50.
Press reset and try different angles
Note:Because of the small space available the accelerations calculated in this simulation are much too large. Precautions:
Ensure that the runway in smooth, free of dust, and does not sag in the middle
At constant velocity the dots must be equally spaced all along the tape (same distance for each 1/50th. sec.). Not possible with this simulation.
Ignore the first few dots on the tape. These are unreliable and too close together for accurate measurement.
Place a ruler right on top of the tape with eye directly above when measuring distances to avoid parallax errors