Measurement of velocity and acceleration

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 and then to give the trolley different accelerations. The velocity of the trolley is measured, using a ticker tape timer, at the start of its journey and at the end and hence the acceleration can be calculated.

Note: In this simulation the angle of the runway can be changed by dragging the mouse along the orange strip

Procedure:

1. Raise the runway slightly.
2. 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 rolls.
3. Press "Get Tape and Ruler". Drag the marker to a suitable dot near the start (left hand side) of the tape.
4. Press "Place Mark". Move 5 dots to the right. Press "Place Mark". The distance between the two marks was travelled in 5/50 of a second. Calculate u, the initial velocity. u = distance / 0.1 m/s
5. Place a mark above the dot on the extreme right of the tape and another on the 5 th dot left of it. The velocity v can be calculated from this section of tape
6. Count the number of dots from the start of the first interval (u) to the start of the second (v). Time is given by: t = no. of dots / 50
7. Calculate the acceleration: a = (v-u)/t
8. Press "Reset". Change the angle of the runway. Repeat steps 1 to 6.

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.)
• 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 when measuring distances to avoid parallax errors