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Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth.
A rocket is launched from atop a 76-foot cliff with an initial velocity of 135 ft/s.
a. Substitute the values into the vertical motion formula h=-16t2+vt+c Let h = 0.
b. Use the quadratic formula find out how long the rocket will take to hit the ground after it is launched. Round to the nearest tenth of a second.
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The equation after substitution is
=
( 135 goes as "v", 76 goes as "c" ). It is your answer to question a).
To answer question b), solve this quadratic equation
=
and take the positive root.
For more similar solved problems see the lessons
- Problem on a projectile moving vertically up and down
- Problem on an arrow shot vertically upward
- Problem on a ball thrown vertically up from the top of a tower
- Problem on a toy rocket launched vertically up from a tall platform
in this site.