Question

Which equation would best help solve the following problem?

Maria releases a javelin 1.5 meters above the ground with an initial vertical velocity of 22 meters per second. How long will it take the javelin to hit the ground?


–4.9t^2 + 22t + 1.5 = 0


–16t^2 + 22t + 1.5 = 0


–4.9t^2+ 22t = 1.5


–4.9t^2 + 1.5t + 22 = 0

Answer 1

it is the first equation - the -4.9 comes form the acceleration of gravity = 9.8 m s-2
The + 1.5 from the 1 5 metres above the ground from which she throws the javelin

Answer 2

Option first is correct!

Explanation:

When an object is thrown above the ground then equation in terms of time (t)

is given by

`-(1)/(2) gt^2+vt+h=0`

where g is acceleration due gravity and v is the initial velocity and h is height above the ground at which it is thrown

since here height and speed is given in MKS system

therefore value of g is also in meter second

that is g = 9.8
`ms^-2`

so equation is given by

`-4.9t^2+22t+1.5 =0` since half of g is 9.8 divided by 2 gives 4.9