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\noindent {\bf Problem statement} After a softball game, the winning
pitcher throws the ball straight up in the air. The height $s$ of the
ball in feet is given by the formula $s=5+48t-16t^2$, where $t$ is the
time after release (measured in seconds).

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\noindent a) The formula is valid only until the ball hits the ground.
When does that happen? 

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\noindent b) Find the instantaneous velocity of the ball at the
following instants: $t=1$, $t=2$ and $t=3$.

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\noindent c) When do you think that the ball reaches its highest
point?  Check your guess by computing the instantaneous velocity at
that instant. How high does the ball get?













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