SOLUTION: pleaseplease help with this question....i submitted this last night but had a few typos. ^2 means squared. i've tried putting these numbers into the quadratic formula but am having

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: pleaseplease help with this question....i submitted this last night but had a few typos. ^2 means squared. i've tried putting these numbers into the quadratic formula but am having      Log On


   

Question 169907: pleaseplease help with this question....i submitted this last night but had a few typos. ^2 means squared. i've tried putting these numbers into the quadratic formula but am having problems with coming up with a trinomial to start from
When an object is released and falls freely, its height, h meters, above the ground after t seconds is represented by the relation h = -0.5t^2g+d, where g is the acceleration due to gravity and d is the initial height of the object before it is released. Since the strength of gravity varies from planet tp planet, the value of g is specific to each planet. Supposed a rock is dropped from a height of 100m on Mars and also Venus. On Mars, g=3.7m/s^2 and on Venus, g=8.9m/s^2. How long does it take the rock to fall to a height of 25m on each planet.
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I did this one yesterday.
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Suppose a rock is dropped from a height of 100m on Mars and also on Venus.
On Mars .g=3.7 m/s2 and Venus,g = 8.9m/s2.How long does it take the rock to fall to a Height of 25 m on each Planet
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In both cases, it's the time to fall 75 meters.
s+=+%28at%5E2%29%2F2 (s is the distance)
On Mars:
(((75 = (3.7t^2)/2}}}
3.7%2At%5E2+=+150
t+=+sqrt%28150%2F3.7%29
t = 6.367 seconds
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On Venus:
The only change is gravitational acceleration, so start with:
t+=+sqrt%28150%2Fg%29
t+=+sqrt%28150%2F8.9%29
t = 4.105 seconds