Word Problem

Question

The International Space Agency has landed a robotic explorer on a planet.  The robot launches a baseball directly upward at 147 ft/s.  The equation for the path of the baseball is:              h = -49t^2 + 147t, where h is the height of the baseball in feet and t is time in seconds.  Assuming no wind, how long will it take for the ball to land on the surface?

Answer 1

h(t) = -49t² + 147t

 

where h(t) is the ball's height at time t.  When the ball lands on the surface, its height is zero:

 

0 = -49t² + 147t

 

factor out the Greatest Common Factor, -49t:

 

0 = -49t(t-3)

 

t = 0 and 3 sec

 

The ball starts at the surface as it is launched at time t=0 sec.  It comes back down and lands on the surface at time t = 3 sec.