Mission Impossible: Special agent Ethan Hunt tries to escape an assassin by jumping horizontally off a flat roof. His goal is to reach a window, two stories or 5.15 m down, on the building across the alley.
Ignore air resistance.
If the alley is 11.9 m wide, how fast must he run when jumping off the roof?
(Start from the basic equations. Clearly state all known quantities. Then show the individual steps of your work. Always show the equation before substituting numbers. Always use units with numbers. Just the right answer will not give full credit.)
d = Vo*t + 0.5g*t^2 = 5.15 m.
0 + 4.9t^2 = 5.15
t^2 = 1.05
Tf = 1.025 s. = Fall time.
Dx = Xo * Tf = 11.9 m.
Xo * 1.025 = 11.9
Xo = 11.6 m/s = Required speed.