Question

Which equation would best help solve the following problem?

Answer 1

Option B:

$-4.9t^2+20t+1.2=0$

General formula for the height(feet) of a projectile over time:

$h(t)=-16t^2+v_0t+h_0$

where h represents height (feet)

t represents time

$v_0$ represents initial velocity

$h_0$  represents initial height(feet)

General formula for the height(metres) of a projectile over time:

$h(t)=-4.9t^2+v_0t+h_0$

where h represents height (feet)

t represents time

$v_0$ represents initial velocity

$h_0$  represents initial height(metres)

Given data in the question:

$h_0=1.2$ metre

$v_0=20$ m/s

To determine the equation to find time:

Substitute $h_0$ and $v_0$ in general formula for the height(metres) of a projectile over time:

$h(t)=-4.9t^2+20t+1.2$

$\Rightarrow -4.9t^2+20t+1.2=0$

Therefore option B is the correct answer.

$-4.9t^2+20t+1.2=0$