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 = -149t^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

Hi Ceejay,

 

At time t=0, h = 0 so the line of symmetry will be half the time when the ball hits the ground.

line of symmetry = -b / 2a

a = -149, b = 147

line of symmetry = -147 / (-2*149)

= 0.49 (rounded to the nearest hundredth) This is when it reaches maximum height.

multiply it by two to find the time when it hits the ground.

2*0.49 = 0.98 seconds