Question

A smoke jumper jumps from a plane that is 1700 ft above the ground. The function y = -16t2 + 1700 gives the jumper's height y in feet at t seconds. A. How long is the jumper in free fall if the parachute opens at 1000 ft? B. How long is the jumper in free fall if the parachute opens at 940 ft?

Answer 1

Answer: (A) 6.6 sec (B) 6.89 sec

Step-by-step explanation:

    y    = -16t² + 1700

 1000 = -16t² + 1700

 -1700             -1700  

  -700 = -16t²

  ÷-16     ÷-16

 43.75 = t²

√43.75 = √t²

   6.6 = t

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    y    = -16t² + 1700

  940 = -16t² + 1700

 -1700             -1700  

  -760 = -16t²

  ÷-16     ÷-16

  47.5 = t²

√47.5 = √t²

  6.89 = t