1. The speed of a bullet as it travels down the barrel of a rifle toward the opening is given by v = (−5.00 × 10⁷) t² + (3.00 × 10⁵) t, where v is in meters per second and t is in seconds. The acceleration of the bullet just as it leaves the barrel is zero. Which answers are correct in the followings?
(A) The length of time the bullet is accelerated is 6.00×10⁻³ s.
(B) The length of time the bullet is accelerated is 3.00×10⁻³ s.
(C) The length of time the bullet is accelerated is 2.00×10⁻³ s.
(D) The speed at which the bullet leaves the barrel is 900 m/s.
(E) The speed at which the bullet leaves the barrel is 450 m/s.