Three simple math questions, two multiple choice

You only need to show work for question #4 :)

D Question 4 A ball is thrown in the air and it's path follows the path modeled by the equation s (t) = -16t' + 20t - 16, where "s" is in ft and "t" is in seconds. Find when the velocity is equal to zero. Show all your work. Upload Choose a File D Question 5 If the velocity of a particle is equal to -30 ft/sec, what does this mean? O Particle is moving upwards O Particle is decelerating O Particle is accelerating O Particle is moving backwards D Question 6 For the particle in #4 find the acceleration at t=3 sec O -100 ft/sec2 O -96 ft/sec2 O -76 ft/sec2 O -32 ft/sec2