Question

A projectile is shot from the ground at a velocity of `4 m/s` at an angle of `pi/3`. How long will it take for the projectile to land?

Answer 1

`0.7"s"`

Explanation:

Use the equation of motion:

`v=u+at`

The vertical component of the initial velocity is `vsintheta`.

At the maximum height the final velocity is zero. We can find the time taken to reach this point.

At this point the equation becomes:

`0=vsintheta-"g"t`

`:.t=(vsintheta)/g`

Converting radians to degrees:

`pi=180^@`

`:.pi/3=180^@/3=60^@`

`:.t=4sin60/9.8=0.35"s"`

The second leg of the flight is when the projectile falls to earth. Because the path is symmetrical this will also be equal to `0.35"s"`.

So total time of flight = `0.35xx2=0.7"s"`