Peoples Physics Concepts

9.6. Rolling Objects http://www.ck12.org

We’ll start by applying Newton’s second law to the bowling ball. The force of friction is the only force in the

x-direction.

ΣFx=max start with Newton’s second law

f=ma put in friction for the net force

f=m

∆v

∆t

substitute in the definition of acceleration.∆tis the time it takes for the ball to begin rolling

f=m

vf−vo

∆t

substitute invfandvo, wherevfis the velocity at the moment the ball begins rolling without sliding

We now have two unknowns in our equation so we’ll use Newton’s second law for rotation as our second equation

to help us solve this problem. Using Newton’s second law for rotation, we’re going to determine a value forvfin

terms of the other values.