Răspuns:
c) a = F/m = 400/100 = 4 m/s2
b) R=ma
R=Fcosα-Ff
R=ma=>Fcosα-Ff=ma
c)Ff=μN
N-mg+Fsinα=0=>N=mg-Fsinα
Ff=μmg-μFsinα=0,2*100*10-0,2*400*0,7=200-56=144 N
Fcosα-Ff=ma<=>400*0,7-144=100a<=>280-144=100a=>136=100a=>a=1,36 m/s²
d)
N=mg-Fsinα=100*10-400*0,7=1000-280=720 N
