calculus problem

Question

The distance of a particle from it's starting point at time t second is given by 8 = 80t - 16t^2

 

what is the velocity of the particle after 2 seconds?

Answer 1

 Of what?

  

 Ok, 

   Velocity is rate of change of displacement:

 

   Given : Displacement 

 

   D = - 16t² + 80t - 8

        

     Velocity is the derivative of displacement:

 

      V =  dD/ dt = -32t + 80

    

      V(2) = -32(2) +80 = 16