For Robbie's glider,
The maximum altitude, t= 22 feet.
For Mellisa's glider, m(s) = 0.4 ( s^3 -11 s^2 + 31s - 1)
dm/dt = 0.4 ( 3 s^2 - 22s + 31 )
= 1. 2 s ^2 - 8.8 s + 12.4 = 0,
Solving the equation, we have : s = 5. 4 or s = 1.9
put the value of s = 5. 4 in m(s) ,
m(s) = 0. 4 ( s ^3 - 11 s^2 + 31 s - 1 )
m ( 5.4 ) = 0.4 ( ( 5.4 ) ^3 - 11 (5.4 )^2 + 31 (5.4) - 1 )
= 1.6416 feet
put the value of s = 1.9
put the value of s= 1.9 in m(s)
m( s) = 0. 4 ( s ^3 - 11 s^2 + 31 s - 1 )
m ( 1.9 ) = 0.4 ( ( 1.9 ) ^3 - 11 (1.9 )^2 + 31 (1.9) - 1 )
= 0.4 x 25. 049
= 10. 0196 m
The glider reaches the greater the greater maximum altitude in the first 6 seconds after lunch is Robbie 's glider (B).