MATH SOLVE

4 months ago

Q:
# Can someone help me on this problem?? I think I’m setting the problem wrong...

Accepted Solution

A:

Answer: Message instructor about this questionStep-by-step explanation:The question does not provide the appropriate information for a suitable answer. The equation tells you height above sea level, but the question asks when the height above ground level will be zero. No information is given as to where ground level is in relation to sea level. The best choice is "Message instructor about this question." Ask the instructor where ground level is in relation to sea level.___In any event, the equation can be made somewhat simpler by factoring -16 ouf of it. Then you get ... h(t) = -16(t^2 -7t -18) = -16(t -9)(t +2)For h(t) = 0, solutions are ... 0 = -16(t -9)(t +2)A product will be zero only when at least one of the factors is zero. t = 9 or -2 . . . . . values that make the factors zeroThe rocket comes back to sea level 9 seconds after launch.___If the rocket is launched from ground level (288 ft), then we want to find t when ... h(t) = 288 = -16t^2 +112t +288Subtracting 288 and factoring out -16, we get ... 0 = -16(t^2 -7t) = -16t(t -7)Solutions are ... t = 0 or t = 7It is no surprise that the rocket is at ground level at t=0, since we have assumed that is where it is launched from. The other solution, t=7, tells us the rocket returns to gruond level 7 seconds after launch._____Possible solutions are ... 9 seconds if "ground level" means "sea level." 7 seconds if "ground level" means "launch height." ... something else if "ground level" is not one of these