A toy rocket moves along a straight line so that its displacement is s(t)=10t2−40t+15 metres for 0≤t≤5. Which statement about its velocity during the interval 0 s<t<2 s is correct?
a) Velocity is positive and increases with time.
b) Velocity is negative and its magnitude decreases with time.
c) Velocity is negative and remains constant throughout the interval.
d) Velocity is negative and its magnitude increases with time.