Question copied word for word 1. A particle of mass m moves in a straight line under the action of force F where F = ms, s being the displacement of the particle from O, a fixed point on the line. When s = -a the velocity of the particle is u. Find the velocity of the particle when s = 0. 2. F = ma or F= -ma (i think...) a = v(dv/ds) 3. If ms = -ma, then s is always equal to -a, so the velocity would always be u, which doesnt look right... Or if I intergate: s = -a s = -v(dv/ds) s^2 = -(v^2) + c replace s with a and v with u. a^2 + u^2 = c s^2 + v^2 = a^2 + u^2 when s = 0, a = 0 v = u Where have i gone wrong?