Question

A box of mass 20 kg is pushed along a rough floor with a velocity 2 m/s and then let go. The box moves 5m
on the floor before coming to rest. What must be the frictional force acting on the box?​

Answer 1

Answer:

mass of body= 20 kg

u= 2m/s

v=0m/s { body comes to rest}

s=5m

$v ^{2} - u ^{2} = 2as$

0-4= 2×a×5

-4 = 10a

a =10/-4

a= 2.5 m/s2

F= ma

f= 5×2.5

f= 12.5 N