6.4 CHAPTER 6. MOTIONIN TWO DIMENSIONS
Step 5 : Using the x and y components, calculatethe final total v
Use Pythagoras’s theorem to find the total final velocity:θ
vfx 1vfy1vftotvftot =�
v^2 fx 1 + v^2 fy 1=�
22 + 4^2
= 4. 5
Calculate the angle θ to find the direction of Player 1’s final veloc-
ity:tan θ =vfy 1
vfx 1
θ = 63. 4 ◦Therefore Player 1 bounces off Player 2 with a final velocity of 4.5
m·s−^1 at an angle of 63.4◦from the horizontal.6.4 Types of Collisions.
Two types of collisions are of interest:
- elastic collisions
- inelastic collisions
In both types of collision, total momentum is always conserved. Kinetic energy is
conserved for elastic collisions, but not for inelastic collisions.