# Roll, Hit and Slip

The rolling object shown is assumed to have a unit radius. It starts rolling from right and hits an obstacle on the Left. Its linear velocity is numerically equal to its angular velocity and it is rolling without slipping before the hit.

You would find the object rolling to the right after the hit. It slips initially and if the friction coefficient os not zero attains the rolling without slipping condition eventually. How quickly it does that depending on the friction coefficient. ( Set it high if you find the object rolling past the right edge before attaining no slip condition )

You can set diffferent initial linear velocities. The angular velocity changes appropriately. You could vary the coefficient of fricition. You can change the height where the hit occurs.

The angular and linear velocities after the hit and the instnataneous linear and angular velcities during subsequent motion are displayed in the gray area on the top. Linear velocity is positive if it is directed towards right and the angular velocity directed in to the plane ( clockwise sense of rotation ) is taken as positive.

Observe the red dots. They indicate the position of the center marked at equal intervels of time. If the dots are equidistant, the velocity is not changing.

You can choose to display velocity vectors of a point on the rim by checking the checkbox marked velocity under display tab.  The red vector is the velocity due to rotation and the yellow vector is the velocity due to translation.

Surendranath.B.