Answer:
A = about 2.2 seconds
B = between 0.2 and 1.7 seconds
Step-by-step explanation:
A .to calculate the time in the air, we have to replache h=0.
h = - 16t + 30t +10
0 = - 16t + 30t +10
For: ax2+ bx + c
x =[ -b ± √b²-4ac] /2a
a=-16 ; b=30 ; c=10
Replacing with the values given:
x =[ -30 ± √(30)²-4(-16)10] /2(-16)
x = [ -30 ± √900 +640] /-32
x = [ -30 ± √1,540] /-32
x = [-30 ± 39.24] /-32
Negative:
x = [-30 -39.24] /-32 = 2.16 seconds = about 2.2 seconds
B. .to calculate this, we have to replache h=15.
15 = - 16t + 30t +10
0 = - 16t + 30t +10-15
0= - 16t + 30t -5
a=-16 ; b=30 ; c=-5
Applying the quadratic formula again:
x =[ -30 ± √(30)²-4(-16)-5] /2(-16)
x = [ -30 ± √900-320] /-32
x = [ -30 ± √580] /-32
x = [-30 ± 24.08] /-32
Positive:
x = [-30 +24.08] /-32 = 0.18 seconds =0.2 seconds
Negative:
x = [-30 -24.08] /-32 = 1.7seconds
Feel free to ask for more if needed or if you did not understand something.
