PLEASE HELP What is the Force of a bike rider with a mass of 45 kg, accelerating 7 m/s^2

Ahonda civic travels in a straight line along a road. its distance x from a stop sign is given as a function of time t by the equation x(t)= î± t2â î² t3, where î± = 1.53 m/s2 and î² = 5.50ã10â2 m/s3 .

Select all of the following that are equal to an impulse of 20 unitsa) force= 5, time= 5.5b) force= 25, time= 0.8c) force= 0.1, time= 200d) force= 10, time= 2(its b, c, and d)(also in order to find answer they have to add to get the unit)ex= 25x.8=20 or .1x200=20

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.