block of wood is pulled by a horizontal string across a rough surface at a constant velocity with a force of 20 N. The coefficient of kinetic friction between the surfaces is 0.3. The force of friction is ?

Question

block of wood is pulled by a horizontal string across a rough surface at a constant velocity with a force of 20 N.  The coefficient of kinetic friction between the surfaces is 0.3.  The force of friction is ?

anonymous · Answer

if it is moving at a constant velocity, than acceleration is 0. if acceleration is zero that F net =0

if F net = Friction + Pull then Friction = -Pull

Therefore Friction = -20

anonymous · Answer

f=20N

anonymous · Answer

@Vannayen, the Vector must be negative

anonymous · Answer

i think that 20 - f =ma
a=0,constant velocity

anonymous · Answer

the frictional force MUST be opposing the direction of motion.

therefore if the motion is cause by a positive Force, then the friction must be negative

anonymous · Answer

thanks guys. I already failed the quiz haha. I forgot to look if someone responded but the help is always greatly appreciated