Question 211170
A punter can kick a football with an initial velocity of 48 feet per second. How many seconds will it take for the ball to return to the ground?(Hint: Use the formula h=vt-16t2*)
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No, h=vt-16t^2
is correct
since v (velocity) is feet/sec and if you didn't multiply with time your units would not work.
.
Since h = height (in feet)
set to zero to find out when it hits the ground
.
0 = vt-16t^2
plugging in the given initial velocity:
0 = 48t-16t^2
0 = 3t-t^2
0 = t(3-t)
t = {0, 3}
.
Well, 0 secs is "before" the punter kicked the ball so we're left with:
t = 3 seconds