CH 5: Friction Force Flashcards
1
Q
what is friction force
A
force that opposes direction of motion
2
Q
what are the two types
A
static and friction
3
Q
whats the general statement about friction
A
Generally 0 < 𝜇𝑘 < 𝜇s
4
Q
what is kinetic friction
A
opposes direction of motion, always
fk = = 𝜇𝑘𝑁
5
Q
what is static friction
A
always opposes the would be direction of motion if static friction wasnt present
as big as it needs to be to oppose motion
up to a max: 𝑓𝑠 ≤ 𝜇𝑠N
6
Q
what about wheels
A
if wheels are sliding to respect to road- skid with no traction (they shouldnt slip at all)
want static friction except it points forward
(car tire would rotate backward w/o friction, so static
friction pushes forward to keep the tire from slipping)
Rolling motion: static friction; skidding: kinetic friction
