We’re measuring the velocity, so that we can find the change in kinetic energy. where should you place the photogate to measure the cart’s velocity? briefly explain your reasoning.

minimum two photogate

Explanation:

The photogate allows us to activate the measurement of time, so we must place at least two of them, one at the beginning of the movement to measure the initial time and another at the end of the movement to measure the final time, of course we must have measured the distance. This gives us the average speed between the two photocells

For measurements with more changes curves, slopes, one photogate must be placed at the beginning of the curve or slope and another at the end.

no. dot product   =0 when vecs at right angles