posted by Derp .
An object is thrown upwards at an initial speed of 19.6m/s from a height of 55m. How long will it take for the object to reach the ground.(from the time it was thrown)
Solve this equation for t:
H(t) = 55 + 19.6 t -4.9 t^2 = 0
Take the positive root. (There will be two solutions.)
Could it also be solved by using
v=u+at for the upward throw;then another motion equation for the upward distance; added to the fall time (sqrt 2h/g) all the way to the bottom?
Yes, that would work also.