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 1
vfy
1
vftot
vftot =
�
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.