How would you set up the following word problem: You are

hitting baseballs. When tossing the ball into the air, your

hand is 5 feet above the ground. You hit the ball when it 

falls back to a height of 4 ft. If you toss the ball with 

an initial velocity of 25ft/sec, how much time will pass 

before you hit the ball? Thanks!



Use the formula h = h0 + v0t - 16t2 since distance is given

in feet. (If distance were in meters, we would have to use

4.9 where the 16 is).



h0 represents the initial height. v0 represents the initial 

velocity, and h is height at the instant when t seconds have

elapsed.



>>...When tossing the ball into the air, your hand is 5 feet 

above the ground...<<



So h0 = 5



>>...you toss the ball with an initial velocity of 25ft/sec...<<



So v0 = 25



So we substitute 5 for h0 and 25 for v0, making our formula



h = 5 + 25t - 16t2



>>...You hit the ball when it falls back to a height of 4 ft...<<



So we wish to find t (the number of seconds) has elapsed at the

instant when the ball is 4 feet high, so we substitute 4 for h

and solve for t:



4 = 5 + 25t - 16t2



16t2 - 25t - 1 = 0



Use quadratic formula, get solutions  



-.04 and 1.6.  We ignore the negative answer.  So the answer is



1.6 seconds approximately.



Edwin 

RELATED QUESTIONS

You are hitting baseballs. When tossing the ball into the air, your hand is 5
feet above  (answered by Edwin McCravy)

Tossing a Ball.  A ball is tossed into the air at 10ft/sec from a height of 5 feet.  How... (answered by Alan3354)

you are on a roof of a building. you throw a ball into the air with a velocity of 32ft/s.  (answered by stanbon,Alan3354)

I've heard that tossing a coin into a fountain will bring me good luck, so I throw a... (answered by nerdybill)

You throw a ball to your friend. The ball leaves your hand 5 feet above the ground and... (answered by josmiceli)

Could you please tell me how to set up the correct equation for this word problem.  "you... (answered by htmentor)

When a ball is thrown up into the air, it makes the shape of a parabola.  The equation S=  (answered by stanbon)

A boy throws a ball straight up into the air it reaches the highest point of its flight... (answered by josmiceli)

1.	Suppose you are in the stands of a World Series baseball game.  A foul ball is hit... (answered by stanbon)