Ball Momentum Calculation: A Simple Guide

[PolyFX]

Homework Statement

A ball moves in the direction of the arrow labeled a below. The ball is struck by a stick which briefly exerts a force on the ball in the direction of the arrow labeled c below.

http://img195.imageshack.us/img195/7387/directionrosette.jpg

Homework Equations

Change in Monetum = Final Momentum - Initial Momentum

The Attempt at a Solution

Don`t you just place the vectors tail to tail and subtract them? If I place vector a tail to tail with c and subtract I get d (tail of vector is at initial and head of vector is at final)

 

[tiny-tim]

Hi PolyFX!

Don`t you just place the vectors tail to tail and subtract them? If I place vector a tail to tail with c and subtract I get d (tail of vector is at initial and head of vector is at final)

No you place them head to tail (in either order) (so the arrows "carry on") …

after all, you're adding momentum to the original momentum, aren't you? …

so add the vectors! ​