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# A young woman is standing on a bridge overlooking a river. If she drops a rock from the bridge, and it takes 1.2 seconds for it to hit the r

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A young woman is standing on a bridge overlooking a river. If she drops a rock from the bridge, and it takes 1.2 seconds for it to hit the river, how many meters did the rock fall?

Guest Feb 16, 2015

#2
+92505
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We have the position at any time is given by

P = -9.8t^2 + v0t + h      where v0 = 0.... and let P = 0 when it hits the water.....so we have

0 =-9.8t^2 + h    and at 1.2 sec, we have

9.8(m/s^2)(1.2 s)^2  = h  = about 14.1 m

CPhill  Feb 16, 2015
#1
+5
Guest Feb 16, 2015
#2
+92505
+5

We have the position at any time is given by

P = -9.8t^2 + v0t + h      where v0 = 0.... and let P = 0 when it hits the water.....so we have

0 =-9.8t^2 + h    and at 1.2 sec, we have

9.8(m/s^2)(1.2 s)^2  = h  = about 14.1 m

CPhill  Feb 16, 2015
#3
+94100
0

Thanks anon for that flash card site.  It looks like it could be really useful for students.

Do you use it yourself or did you just google this question?

Melody  Feb 17, 2015