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August 21, 2014

August 21, 2014

Posted by **Kacy** on Tuesday, September 21, 2010 at 1:47am.

(a) If you drop the stone, how long does it take for it to fall to the base of the gorge?

s

(b) If you throw the stone straight down with a speed of 22.5 m/s, how long before it hits the ground?

s

(c) If you throw the stone with a velocity of 22.5 m/s at 25.0° above the horizontal, how far from the point directly below the bridge will it hit the level ground?

- physics -
**Anonymous**, Wednesday, September 22, 2010 at 2:37amdo u go to wayne state?

- physics -
**Henry**, Wednesday, September 22, 2010 at 7:15pma. d = 0.5gt^2,

66 = 0.5 * 9.83 t^2,

66 = 4.915t^2,

t^2 = 66 / 4.915 = 13.4,

t = sqrt(13.4) = 3.66 s.

b. d = Vo*t + 0.5gt^2,

66 = 22.5t + 0.5 * 9.83t^2,

66 = 22.5t + 4.915t^2,

4.915t^2 + 22.5t - 66 = 0,

Use Quadratic Formula to find t:

t = (- 22.5+- sqrt(506.25 + 1297.56))/

9.83,

t = (-22.5 +- 42.47) / 9.83,

t = 2.03 or -6.61, select positive t:

t = 2.03 s.

c. y = Ver.=22.5 m/s * sin25 = 9.5m/s

d(up) = d(down),

Vo*t = 0.5gt^2,

9.5t = 0.5 * 9.83t^2,

9.5t = 4.915t^2

4.915t^2 - 9.5t = 0,

Factor out t:

t(4.915t - 9.5) = 0,

t = 0: 4.915t - 9.5 = 0, 4.915t = 9.5,

t = 1.93 s (Ver),

d = Ver. = 9.5 m/s * 1.93 s = 18.4 m,

d = R = 18.4 m /sin25 = 43.5 m,

d = Hor. = 43.5 m * cos25 = 39.5 m = distance stone lands.

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