So, I attached a photo of what the figure given looks like. Here is the corresponding problem: The figure represents the total acceleration of a particle moving clockwise in a circle of radius 2.50 m at a certain instant of time. At this instant, find (a) the radial acceleration, (b) the speed of the particle, and (c) its tangential acceleration. I know that atot = ar + at, where ar = -v^2/r and at = d|v|/dt. I'm not sure how to do this problem, or at least start it off. I did plug some numbers (where a = 15 and radius is 2.50 m) into the equation, but I do not think it got me anywhere. I have to somehow use the angle or even the radius and angle together, for starters. And then there is a slight problem in the fact that these terms of radial and tangential acceleration confuse me. Care to explain, please?