- #1

Blake_ap1

## Homework Statement

I need help finding the appropriate expression to use to add a "new calculated column" to produce a vertical velocity vs time graph in Logger Pro. The lab consisted of a ball tied to a rope, creating a pendulum. The Go! Motion sensor was set up to record the oscillations. The sensor recorded horizontal displacement and horizontal velocity. The x position vs time was calculated using the expression x = "R" - Ravg. The horizontal velocity was calculated using the expression y = L - sqrt(L^2-"x"^2).

I do not know what expression to use to find the vertical velocity.

R avg = (Rmax + Rmin) / 2 = 1.476 m. The section reads.

The horizontal velocity (vx) of the oscillating object was automatically calculated by the program. To find the vertical velocity (yy), create a new calculated column using the equation derivative("y"). The derivative (or dy/dt) is the rate of change of the vertical position with time. You should be able now to calculate the magnitude (v) of the resultant velocity. What is the appropriate equation for this calculation? Display vx, vy and v together on the same graph and include it in your lab report. Comment on the relationship between the three graphs.

Can someone point me in the right direction? Attatched are releative photos and the lab manual. I am doing Lab 4, and Working on the vertical velocity vs time section on page 25

**Relevant equations**

**The attempt at a solution**

I'm having trouble Deriving the expression for dy/dt. I've hit a deadlock. I know I have to change things to the manner of y and θ. I know y = L - Lcosθ & x = Lsinθ

I know my expression needs to be along the lines of vy = (LxVx)/ (sqrt(x

^{2}+(L-y)

^{2}) + Ly)