Ffrict = Âµ â¢ Fnorm. Return to Top. The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force-sliding and static friction. Though it is not always the case, the friction force often opposes the motion of an object.
Answers from Sandhya Pruthi, M.D. No, caffeine doesn't appear to cause breast cysts (fibrocystic breast changes), a noncancerous (benign) breast disease. There's also no evidence to suggest a link between caffeine and breast cancer. Anecdotally, some women report that breast pain symptoms improve when they go off caffeine or reduce the amount of caffeine in their diets. Although no research has documented this effect, it's OK to go to go caffeine-free to see if it relieves discomfort from breast cysts.
1 Some research also suggests an increased risk of bladder cancer in male coffee drinkers60,62. Further work is required to understand these associations in more detail.  Evidence for a dose response relationship between coffee intake and bladder cancer is also limited.