the height of an object after t seconds is given by f(t)=-5t^2+20t (a) find the height of the object after 2 seconds, and includ
e the correct units with your answer. (b) find the average (vertical) velocity of the object on the time interval [0,2]. show your work, include the correct units, and. circle your final answer. (c) find the instantaneous velocity at t=2
