Question

A rock is thrown vertically upward from the edge of a cliff. It leaves your hand at a point even with the edge at a speed of 25 m/s. The rock is then in free fall. On its way back down, it misses the edge of the cliff and continues its fall towards the river. Using the four generic kinematics equations listed below, provide your simplified equations using a coordinate system whose y axis is positive down and the x axis positive right such that the origin is located at the edge of the cliff

tion: x=xo + vt 2 22a(-

Answer 1

Given u = -25 m/s a = + 9.8 m/s^2 t = t Along x-axis x_0 = 0 t = t V_x = V_x = 0 x = x_0 + Vt x = (0) + (0) t x = 0 Along y-axis: - Displacement in t second x = x_0 + v_0 t + 1/2 at^2 x = 0 - 25t + 1/2 (+ 9.8) t^2 x = -25t + 4.9t^2 (2) Velocity in t sec V = V_0 + at V_0 = -25 m/s a = + 9.8 m/s^2 t = t V = -25 + 9.8 t (3) V^2 = V^2_0 + 2a(x - x_0) V^2 = (25)^2 + 2(9.8) (x - 0) V^2 = 625 + 19.6 x (4)