I think it’s B hope it helps:)
Answer:
Hey shaikaadil700 !
<u> </u><u>Lubricating</u><u> </u> of rough surfaces reduces friction.
Explanation:
• Lubricating is the smoothening or polishing of the surfaces

true
Explanation:
this is because melting point and boiling point decreases down the group because they are held together by attractions between positive nuclei and delocalised electrons
Explanation:
formula for force is:
force=mass × acceleration
but in case of friction
force =coefficient of friction × Normal Reaction
F. = u × R
U = F/R
but when placed horizontally
R= M×G
M=mass=60kg
G=Gravity(10m/s or 9.8m/s)
F=140N
U=140/60×10
U=140/600
U=0.2333333333
approximately to 3 significant figures
U=0.233
if i am correct rate it 5 star