# Calculating Friction due to rotation from ball bounce? [duplicate]

This question already has an answer here:

In this question asked by codemonkey, The rotation will depend upon:

upon impact, on:

• Initial Speed of the ball hitting the surface (magnitude of ball velocity vector)
• Friction co-efficient of ball & surface (constants for simulation)
• Angle between ball impact velocity vector and the surface normal

Everything is fine except for second point. How the friction coefficient of ball and surface should be taken into account?

EDIT: The problem with my approach is i donot know the impact time of the collision. If say the time of impact is dt, Vn1 is the final velocity parallel to the surface then

mass*(Vn1-Vn0)/dt X r = torque


Then i can calculate the angular velocity produced by this torque if it acts for dt time.

also

Vn1= Vn0 + accelaration* dt


where

accelaration+angular_accelaration*r


Please correct me if i am wrong. Also how do i calculate dt?