If any problem involving circular motion, which way does the acceleration vector point ?

The acceleration vector always points towards the centre of the motion. This is referred to as centripetal acceleration. It accounts for the centripetal force that tends to pull the object in circular motion towards the centre of motion.

Consider the diagram below;

it illustrates a body in circular motion along the black circle, with the acceleration vector a shown by the orange arrow pointing towards the centre of motion and the velocity vector v shown by the green arrow pointing tangentially away from the circumference.

colorectal cancer may also develop from areas of abnormal cells in the lining of the colon or rectum. this area of abnormal cells is called dysplasia and is more commonly seen in people with certain inflammatory diseases of the bowel such as crohn's disease or ulcerative colitis.

show the wavelengths of a wave. show the crests of a wave.