Two particles A and B are moving as shown in the figure.

Their total angular momentum about the point O is

• 9.8 kg m² / s

• zero

• 52.7 kg m² / s

• 37.9 kg m² / s

A circular disc rolls on a horizontal floor without slipping and the centre of the disc moves with a uniform velocity v. Which of the following values of the velocity at a point on the rim of the disc can have ? 

• v

• − v

• 2v

• Zero