We know the acceleration is 32 (down), so say a(t) = -32. Take the integral of that to get velocity which is v(t) = -32t + c. We know c is 48 from before, so v(t) = -32t + 48. Take the integral again to find the displacement, which is x(t) = -16t^2 + 48t + c where c = 400. Now set x(t) = 0 to find the time. So -16t^2 +48t + 400 = 0
So -t^2 + 3t + 25 = 0 solve with the quadratic formula to get t = 6.72
Now plug that into the velocity equation to get -167.045 ft/s
Hope this helps
May 18th, 2015
Are you studying on the go? Check out our FREE app and post questions on the fly!