Question: I am trying to solve h=−4.9t2+4.9t+s for 't' but it doesnt make sense. Can you share with me the correct steps.
What you have there is a formula, h(t) = -4.9t^2 + 4.9t + s, which gives the height of a body, in metres, after t seconds, when projected vertically upwards with an intiial velocity of 4.9 m/s, starting from s metres above the ground (s is a constant).
When you are given a formula, and asked to solve it, that means that you have to set the folmula equal to zero and solve for the unknown. So,
h(t) = -4.9t^2 + 4.9t + s = 0
4.9t^2 - 4.9t - s = 0
Using the quadratic formula, x = {-b ± √(b^2 - 4ac)}/(2a),
t = {4.9 ± √(4.9^2 - 4*4.9*(-s))}/(2*4.9)
t = {4.9 ± √(24.01 + 19.6s)}/(9.8)
t = 0.5 ± √(0.25 + s/4.9)
When you have a value for s (the starting point above the ground) you can solve for exact values.