3. From joint angle plots, estimate where the velocity of each joint will be positive, where it will be negative and where the velocity will be zero. Note that velocity is the rate of change of position and can be measured as the slope of the position graph. a. Copy your ankle and knee angle figures from above and remove the descent data. b. Draw vertical lines where the velocity curve would be 0. Indicate whether the velocity is positive or negative for this period of time by writing a positive or negative sign in between the lines