h = Vo*t + 0.5g*t^2 = 34.9.
6.85t + 4.9t^2 = 34.9,
4.9t^2 + 6.85t - 34.9 = 0,
Quad. Formula:
t = (-6.85 +- sqrt(6.85^2 + 684.04))/9.8 = 2.06 s. to hit the pavement.
V = Vo + g*t = 6.85 + 9.8*2.06 = 20.2 m/s.
HELP :)
A man who is standing on the roof of a building throws a baseball vertically downward toward the sidewalk at a speed of 6.85m/s. The sidewalk is 34.9m below the roof. Calculate the speed of the ball just as it hits the pavement.
3 answers
Correction: V = 27.1 m/s.
Another Method:
V^2 = Vo^2 + 2g*d = 6.85^2 + 19.6*34.9 = 730.963.
V = 27.05 m/s.
V^2 = Vo^2 + 2g*d = 6.85^2 + 19.6*34.9 = 730.963.
V = 27.05 m/s.