Home › UAE MoE Grade 12 › Physics › Friction, Drag and Elasticity › What does friction do to the relative motion of …
What does friction do to the relative motion of two surfaces in contact?
AIt opposes their relative motion
BIt speeds up their relative motion
CIt has no effect on their motion
DIt reverses their relative motion
Answer & Solution
Correct answer: A. It opposes their relative motion
1. Friction arises wherever two surfaces are in contact with one another.
2. It is a force, and its effect is always to oppose relative motion between those surfaces.
3. So it acts against the motion that is happening, or against the motion being attempted.
4. It can never drive the surfaces faster or drive them backwards past rest.
_Source: OpenStax College Physics (CC BY 4.0), Ch 5 "Further Applications of Newton's Laws: Friction, Drag, and Elasticity", section Friction_
Related questions
The tip of a probe dragged across a material is deformed by atomic-scale friction. The forWhat happens to the downward force of gravity on a skydiver as their speed rises?Which two forces act on a skydiver falling through air, once buoyancy is ignored?What would a nearly friction-free environment save on a large scale?What kind of characteristics of friction are the simple rules taught at school?Which of these is the standard everyday example of kinetic friction acting?Why do two surfaces become warm when they are rubbed together?Adding a heavy box on top of a crate makes it harder to push. Why?