Search results
Results from the WOW.Com Content Network
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. [2][3] Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of the processes involved is called tribology, and has a history of more than 2000 years.
Braking distance refers to the distance a vehicle will travel from the point when its brakes are fully applied to when it comes to a complete stop. It is primarily affected by the original speed of the vehicle and the coefficient of friction between the tires and the road surface, [Note 1] and negligibly by the tires' rolling resistance and vehicle's air drag.
Stokes' law is the basis of the falling-sphere viscometer, in which the fluid is stationary in a vertical glass tube. A sphere of known size and density is allowed to descend through the liquid. If correctly selected, it reaches terminal velocity, which can be measured by the time it takes to pass two marks on the tube.
, the Darcy friction factor (also called flow coefficient λ [9] [10]). For laminar flow in a circular pipe of diameter D c {\displaystyle D_{c}} , the friction factor is inversely proportional to the Reynolds number alone ( f D = 64 / Re ) which itself can be expressed in terms of easily measured or published physical quantities (see ...
Sliding friction (also called kinetic friction) is a contact force that resists the sliding motion of two objects or an object and a surface. Sliding friction is almost always less than that of static friction; this is why it is easier to move an object once it starts moving rather than to get the object to begin moving from a rest position.
The first general equation of motion developed was Newton's second law of motion. In its most general form it states the rate of change of momentum p = p(t) = mv(t) of an object equals the force F = F(x(t), v(t), t) acting on it, [13]: 1112. The force in the equation is not the force the object exerts.
In fluid dynamics, the drag equation is a formula used to calculate the force of drag experienced by an object due to movement through a fully enclosing fluid. The equation is: where. is the drag coefficient – a dimensionless coefficient related to the object's geometry and taking into account both skin friction and form drag.
The frictionless plane is a concept from the writings of Galileo Galilei. In his 1638 The Two New Sciences, [1] Galileo presented a formula that predicted the motion of an object moving down an inclined plane. His formula was based upon his past experimentation with free-falling bodies. [2] However, his model was not based upon experimentation ...