Finding Velocity from Ticker Tape

Finding Velocity
The velocity of motion can be determined by using ticker tape through the following equation:

Caution!:
t is the time taken from the first dot to the last dot of the distance measured.

Example:

The diagram above shows a strip of ticker tape that was pulled through a ticker tape timer that vibrated at 50 times a second. What is the
  1. time taken from the first dot to the last dot?
  2. average velocity of the object that is represented by the ticker tape?

Answer:

a. There are 15 ticks from the first dot to the last dot, hence

Time taken = 15 × 0.02s = 0.3s

b. Distance travelled = 15cm