document.write( "Question 139518: hello....I am stumped...hope you can help...Question: Assume Joe Ball hits a major league pop-up (straight upward) on a Johnny Bench 90mph pitch. The function that describes the ball's height (in feet/second) is: h(t) = -16t^2+132t h(t) is height, t = is seconds...How many seconds for the ball to go up and back down? How high does the ball go? I came up with answers 4.125 for ball to go up and down and 272.25 feet for how high ball goes up (correct??)...but here's the stumper: it's now asking to repeat problem using planet Mercury. How do I complete this? (FYI, Mercury is 38% of Earth)....Hope you can help and show me the correct formula and answers..Thank you \n" ); document.write( "
Algebra.Com's Answer #101713 by Earlsdon(6294)![]() ![]() ![]() You can put this solution on YOUR website! Let's look at part I of the problem: \n" ); document.write( "I) \n" ); document.write( "a) How many seconds for the ball to go up and down? \n" ); document.write( "In other words, how many seconds for the ball to return to the ground? \n" ); document.write( "Starting with the given formula: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "So we have: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Add 16t to both sides. So... \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "The ball returns to the ground in 8.25 seconds. \n" ); document.write( "b) How high does the ball go? \n" ); document.write( "You'll need to find the value of t at the vertex of the parabola described by the given equation. This is given by: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "II) For this problem to be solved for the planet Mercury whose gravitational force is 38% that of earth's, let's look at the original formula for the height of an object propelled upwards: \n" ); document.write( " \n" ); document.write( "Here, the acceleration due to gravity is: g = 32 ft/second squared for earth. \n" ); document.write( "For Mercury, g = 0.38(32)ft/second squared = 12.16 feet/second squared. \n" ); document.write( "So the formula for the planet Mercury becomes: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "a) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "The time to reach its maximum height is: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |