How Can a Mask, Light Gate, and Motion Computer Measure Instantaneous Speed?

[Revolutionz]

Homework Statement

Describe how you would use a mask, light gate and motion computer to measure the instantaneous speed of the trolley at the bottom of the slope. (specify what the computer measures, what it calculates and what has to be programmed into its memory.

(3 Marks)

Homework Equations

N/A

The Attempt at a Solution

This came up in my homework questions that has to be in for monday.
im having a lot of trouble to get max marks out of this question.

Here's what i have.
You set up a light gate on the slope and at the bottom. you release the trolley at the top of the slope and the computer measures the time took from light gate 1 to light gate 2 and calculates the acceleration. But i don't knw what has to be programmed into it memory

If anyone could help me get max marks and improve my answers, i will be grateful.

 

[CompuChip]

Suppose the computer measures a time of 1 second. What other information do you need to find the instantaneous speed? Does it matter where on the slope you put the first gate?

Otherwise, try doing the calculation by hand. Suppose you are only given the time (e.g. 1 second), go through the calculation, and box all the additional information you have to use to do the calculation. If possible, give a formula which only gives the answer in terms of the measurement and the additional parameters you specified, such that a computer would just have to fill in the numbers to find the answer.