Un treno si muove per un certo tratto rettilineo con moto uniformemente accelerato (a = 15 m/s^2). Un oggetto di massa m = 2,0 kg rimane in quiete nonostante l'accelerazione del treno grazie all'attrito con il pavimento. Quanto vale il modulo della forza d'attrito?

"i have always loved contemporary art and made it a general goal to work within the field. after a few nonprofit internships at museums and galleries, i decided to try the for-profit art world and was offered a job as the ad assistant at the magazine. i much prefer the pace of the for-profit art community and have stayed with the company for three years, with a promotion to an account manager last spring."

i just did this and got a 100.