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crickamaxwell
Heather hits a tennis ball upward with an initial speed of 32 feet per second. After how many seconds does the ball hit the ground? Use the formula h = rt − 16t^2 where h represents height in feet and r represents the initial speed.
You have all you need to solve this problem. Where are you stuck?
Basically, you want to find a solution to the equation\[0=32t-16t^2,\]where \(t\neq0\).
You should also note that \[h=h_0 + v_0t+\frac{1}{2}gt^2\] where h is your height, h_0 is your initial height when you threw the ball, v_0 is your initial velocity, and g is the force of gravity (at 32ft/sec^2) You may run into this equation again in physics and this is the equation that is used there.
You could also derive it from an ordinary differential equation if you feel like it...