Hi, Can anybody help with the following: A point particle moves in a plane with trajectory given by r(t) = R [θ (t)]^3/2, where R is a constant. The angle θ in radians increases in time according to the equation θ (t) = 1/2 α t^2, where α is a constant whose numerical value is α = 1 s^-2. a. Sketch the trajectory of the particle. b. Compute the time t > 0, if any, for which the radial and tangential components of the velocity of the particle coincide. c. Compute the time t > 0, if any, for which the acceleration of the particle is purely tangential. d. Compute the time t > 0, if any, for which the radial acceleration of the particle is twice its tangential acceleration. I really am struggling with this question. I'm not even sure about sketching the trajectory, which is usually the least I can do in these type of questions! Can anybody help and explain it in really simple terms. Thanks for any help with this.