A driver applies the brakes on seeing the red traffic signal 400 m ahead. At the time of applying brakes, the vehicle was moving with $15 \mathrm{~m} / \mathrm{s}$ and retarding at $0.3 \mathrm{~m} / \mathrm{s}^2$. The distance covered by the vehicle from the traffic light one minute after application of brakes is

The acceleration of a moving body can be found from

The position '$$x$$' of a particle varies with a time as $$x=a t^2-b t^3$$ where '$$a$$' and '$$b$$' are constants. The acceleration of the particle will be zero at

Two bodies $$A$$ and $$B$$ start from the same point at the same instant and move along a straight line. body $$A$$ moves with uniform acceleration $$a$$ and body $$B$$ moves with uniform velocity $$v$$. They meet after time $$t$$. The value of $$t$$ is