9709 P42 - Jun 2023 - Q6
3753
A particle P starts at rest and moves in a straight line from a point O. At time t s after leaving O, the velocity of P, v m/s, is given by \(v = bt + ct^{\frac{3}{2}}\), where b and c are constants. P has velocity 8 m/s when \(t = 4\) and has velocity 13.5 m/s when \(t = 9\).
- Show that \(b = 3\) and \(c = -0.5\).
- Find the acceleration of P when \(t = 1\).
- Find the positive value of t when P is at instantaneous rest and find the distance of P from O at this instant.
- Find the speed of P at the instant it returns to O.
