# Velocity problem determining x and y components

An object undergoing parabolic motion travels 100 m in the horizontal direction before returning to its initial height. If the object is thrown initially at a 30° angle, determine the x component and the y component of the initial velocity. (Neglect any effects due to air resistance.)

I am not sure how to go about solving... I got an initial vector from the throw but I dont think it can be the initial velocity vector since I have no judgment of time.. could someone show me the process of solving this?

HallsofIvy
Homework Helper
If we let "$v_x$" and "$v_y$" be the components of velocity in the x and y directions, respectively, then $x= v_xt$ and $y= -4.9t^2+ v_yt$ so we have $y= -4.9t^2+ v_yt= 0$ (the projectile hits the ground) and $x= v_xt= 100$ (the projectile hits the groud after 100 m). The fact that "the object is thrown initially at a 30° angle" means that $v_y/v_x= tan(30)$. That gives you three equations to solve for the three values, t, $v_x$, and $v_y$.

rl.bhat
Homework Helper
If vsinθ is the y component of the velocity, what is the time the projectile takes to return to its Initial height?
If vcosθ is the x component of the velocity, what is the expression for the range x?

An object undergoing parabolic motion travels 100 m in the horizontal direction before returning to its initial height. If the object is thrown initially at a 30° angle, determine the x component and the y component of the initial velocity. (Neglect any effects due to air resistance.)

I am not sure how to go about solving... I got an initial vector from the throw but I dont think it can be the initial velocity vector since I have no judgment of time.. could someone show me the process of solving this?

The time taken for the object to travel horizontally 10m is equal to the time taken from launching up and back to same level.

It is a single body, at same place(different x and y coordinates) and at same time.