7 ft 5 ft 60 yd Determine the time of flight of the football

7 ft 5 ft 60 yd Determine the time of flight of the football. (10 points) O A 3.66s B.3.86s O C3.46 s D.2.56 s QUESTION 9 Determine the initial velocity Vo of the football. (15 points) e A 56 fts @ B. 66 ft/sc. 81 ft/s D. 76 ft/s

Solution

For the vertical journey of the football,

y= -2 ft; g=-32.174 ft/s²; v_y = v*sin(30) = 0.5*v {v_o=v say}

using, y=ut + 0.5at²

-2 = 0.5*v*t -32.174*0.5*t²

For the horizontal motion,

60 yd = 180 ft

180 = v*cos(30) * t

v = 180/(t*cos(30))

putting the value of v in vertical motion equation,

-2 = 0.5*v*t -32.174*0.5*t²

-2 = 0.5*180*sec(30) -32.174*0.5*t²

solving the above equation, we get,

t= 2.566 seconds

option D

9) putting the value of t in horiztonal equation,

180 = v*cos(30) * t

180 = v*cos(30) * 2.566

v= 81 ft/s

option c