SOLUTION: an angry construction worker throws his wrench downward from a height of 128 feet with an initial velocity of 32 feet per second. the height of the wrench above the ground after t
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Question 282442: an angry construction worker throws his wrench downward from a height of 128 feet with an initial velocity of 32 feet per second. the height of the wrench above the ground after t seconds is given by; S(t) = 16t^2 -32t + 128.
a. what is the height of the wrench after 1 second?
b. how long does it take for the wrench to reach the ground? Answer by solver91311(24713) (Show Source):
Unless there is some sort of anti-gravity machine attached to this wrench, then your expression for height as a function of time is incorrect. The physics of objects near the earth surface as I understand them demands that the function be:
Now, to answer part a, read the problem again, specifically this part: "the height of the wrench above the ground after seconds is given by:" Let's read that again: "the height of the wrench above the ground after seconds is given by:" So doesn't it make sense that the height of the wrench above the ground after 1 second would be given by:
?
Just do the arithmetic.
Part b). The ground is height 0. So if:
then
Just solve the quadratic -- it factors quite neatly, in fact. Hint: Divide through by -16 first. As with any quadratic, you will get two roots. You can discard the negative one because the wrench certainly didn't hit the ground some number of seconds before the guy threw it. Your answer is the positive root.
