A projectile is shot from the ground at a velocity of #13 m/s# and at an angle of #(2pi)/3#. How long will it take for the projectile to land?
Let's breakdown the velocity into x and y parts using trigonometry.
The x axis has a cosine term and the y axis has a sine term, so
We don't care about the x coordinate, because we only want to know how long it takes for the y coordinate to go back to 0.
We can use basic kinematics:
We want to know when this hits the ground, i.e. when
which is 0 when
The first makes sense because when we first shoot it off, it is at the ground,
The second solution is