# Understanding horizontal and vertical components of a falling object

1. Sep 29, 2008

### science_rules

I want to understand this: In the case of a dropped object, the horizontal component of the velocity with which the object hits the ground is not the same thing as the horizontal velocity itself, am i right? The horizontal component of the velocity when the object hits the ground means the horizontal component of the initial velocity?
Say an object is dropped from a plane at a certain speed(horizontal velocity), air resistance is negligable. The horizontal component of the velocity with which the object hits the ground would be zero because air resistance is negligable?

2. Sep 29, 2008

Assuming air resistance is negligible, the horizontal component of initial velocity and of final velocity are equal, but they are not equal to zero (unless the object has been dropped straight downward along the y-axis, in which case there is no horizontal component). So when the object hits the ground, the magnitude of its velocity in the horizontal direction is exactly the same as the magnitude of its velocity in the horizontal direction at the moment is was released/launched.

The horizontal ACCELERATION is zero, though, because no force is acting upon the object in the horizontal direction.

Keep in mind that in the sort of situation you're talking about, the horizontal component is completely separate from the vertical component. One has nothing to do with th other, unless you're combining them to look at the complete trajectory of the object.