Mini-Quiz: Gravity Time Equations for Objects Projected Downward

1. How long does it take to reach 118 m/s if the initial velocity downward is 20 m/s?

   1 secondGood try, but not right. Select another answer. 9.8 secondsSorry, not correct. Try another button. 10 secondsCorrect. You know about gravity.

2. If t = [−vi + √(vi2 + 2gy)]/g, how long does it take to reach 64 ft if the initial velocity is +32 ft/s?

   t = [−32 + √(322 + 2*32*64)]/32 secondsThat is Correct. You must be good in math. t = [−32 + √(322 + 2*9.8*64)]/9.8 secondsOops! Wrong answer. Re-read the question and try again. t = [32 + √(322 + 2*32*64)]/32 secondsSorry, not correct. Try another button.

3. What is the time when the displacement is zero?

   t = [−vi + √(vi2 )]/g = 2vi/g secondsGood try, but not right. Select another answer. t = [−vi + √(vi2 )]/g = 0 secondsCorrect. You know about gravity. y cannot equal zeroOops! Wrong answer. Re-read the question and try again.

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