Option B:
[tex]-4.9t^2+20t+1.2=0[/tex]
General formula for the height(feet) of a projectile over time:
[tex]h(t)=-16t^2+v_0t+h_0[/tex]
where h represents height (feet)
t represents time
[tex]v_0[/tex] represents initial velocity
[tex]h_0[/tex] represents initial height(feet)
General formula for the height(metres) of a projectile over time:
[tex]h(t)=-4.9t^2+v_0t+h_0[/tex]
where h represents height (feet)
t represents time
[tex]v_0[/tex] represents initial velocity
[tex]h_0[/tex] represents initial height(metres)
Given data in the question:
[tex]h_0=1.2[/tex] metre
[tex]v_0=20[/tex] m/s
To determine the equation to find time:
Substitute [tex]h_0[/tex] and [tex]v_0[/tex] in general formula for the height(metres) of a projectile over time:
[tex]h(t)=-4.9t^2+20t+1.2[/tex]
[tex]\Rightarrow -4.9t^2+20t+1.2=0[/tex]
Therefore option B is the correct answer.
[tex]-4.9t^2+20t+1.2=0[/tex]
