"First; let's calculate the friction force:"First; let's calculate the friction force:
F_f=u_k*GFf=uk⋅G
G:"weight of object G=m.g"G:weight of object G=m.g
u_k:" coefficient of friction"uk: coefficient of friction
F_f=u_k*m*gFf=uk⋅m⋅g
F_f=20/g*m*gFf=20g⋅m⋅g
F_f=20mFf=20m
a=F_f/ma=Ffm
a=(20m)/m " "a=20 m/s^2 " acceleration of object"a=20mm a=20ms2 acceleration of object
"when object is stops ,the final velocity of its is zero"when object is stops ,the final velocity of its is zero
v_f^2=v_i^2-2*a*Sv2f=v2i−2⋅a⋅S
v_f:"final velocity"vf:final velocity
v_i:"initial velocity"vi:initial velocity
a:"acceleration"a:acceleration
"S:"displacement"S:displacement
0=3^2-2*20*S0=32−2⋅20⋅S
9=40*S9=40⋅S
S=9/40S=940
S=0.225 mS=0.225m