Give any two salient features of static Friction and Kinetic Friction.

Explanation

Static friction: Static friction is the force which opposes the initiation of motion of an object on the surface. The magnitude of static force `f_(s)` lies between.
`=lef_(s)lemu_(s)N_(s)`
`mu_(s)`- coefficient of static friction
N- Noemal force
Kinetic frition : The frictionl force excerted by surface when an object slides is called as kinectic friction . Also called as sliding friction or dynamic friction,
(ii) To move an object-push ior pull? Which is easier? Explain
When a body is pushed at an arbitrary angle `theta (0 "to"(pi)/(2))`, the applied force F can be resolved into two componentes as F `sin theta` parallel to the surface and F `cos theta ` perpendiculer to the surface as shown in figure. The total downward force acting on the body is mg+F `cos theta` . It implies that the normal force acting on the body increas. Since there is no acceleration alon the vertical direction the normal force N is equal to.
`N_(PUSH)=mg+F costheta`
As a result the maximal static friction also increases and is equal to
`f_(x)^(MAX)=mu_(r)N_(PUSH)=mu_(5)(mg+fcostheta)`
Equation (2) shows that a greater n force needs to be applied to push the object into motion .

When an object is pulled at an angle `theta`, the applied force is resolved into two components as shown in figure. the total downward force acting on the object is
`N_(pull)=mg-Fcostheta`

Equation (3) shows that the normal force is less than `N_(push)`. from equations (1) and (3), it is easier to pull an object than to push to make it move.