Question 1079156: Sir Isaac Newton XIV, a descendant of the famous physicist and mathematician, takes you to the top of a building to demonstrate a physics property discovered by his famous ancestor. He throws your math book straight up into the air. The book's distance, s, above the ground as a function of time, t, is modeled by s=-16t^2+16t+32
a) When the book strikes the ground, what is the value of s?
b) Write an equation that you must solve to determine when the book strikes the ground.
c) solve the equation from problem b by factoring.
d) Are both solutions to the equation (t=2 and t=-1) also solutions to the question, "At what time does the book strike the ground"? Explain.
e) You want to know at what time the book is 32 feet above the ground. Write a quadratic equation that represents this situation.
f) Solve the equation from problem e by factoring.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! -16t^2+16t+32=0 when it hits the ground.
a) 0 is the value of s
b)-16t^2+16t+32=0
c)-16(t^2-t-2)=0 and (t-2)(t+1)=0, so t=2 or -1
d) only the t=2 is a solution since time has to be positive.
e) -16t^2+16t=32=32; -16t^2+16t=0, t=0, t=1, only 1 makes sense.
(the building is 32 feet tall.)
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