Q3
A particle moves along a straight line passing through O. Its displacement, s metres, from O at t seconds after passing through O is given by s = 80t - 4t ^ 2
(a) When is the particle
(i) 300 m to the right of O ?
(ii) 500 m to the left of O ?
(iii) passing through O again?
(b) Find the time interval when
(i) the particle moves to the right
(ii) the displacement is negative.
(Assume motion to the right is positive) [Ans: (a) t
= 5, 15; 25; 20; (b) 0 < t < 10 , t > 20s ]
