The distance covered by a car at a time, t is given by x = 20t + 6t4, calculate (i) the instantaneous velocity when t = 1

(ii) the instantaneous acceleration when t =1

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.