In an activity, a wooden block is pulled with a spring balance across three surfaces. The reading just as the block starts to move is: glass sheet 2 N, wooden table 3.5 N, sandpaper 6 N. (a) On which surface is friction greatest? (b) Arrange the surfaces in increasing order of friction. (c) What do you conclude about friction?

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Static and Kinetic Friction, Factors Affecting Force of Friction | PadhAiPro

Question

TextStatic and Kinetic FrictionFactors Affecting Force of Friction

Meena rolls a marble with the same push on a grassy lawn and on a smooth cemented floor. The marble stops sooner on the lawn because:

Two friends find it hard to start moving a heavy almirah, but once it starts sliding it is easier to keep it moving. The reason is:

Assertion (A): Friction opposes the relative motion between two surfaces in contact. Reason (R): Friction is a non-contact force.

Friction arises because of tiny irregularities (bumps) on the two surfaces in contact.

Why is fine powder sprinkled on a carrom board before playing?

Why do athletes wear shoes with spikes, and why do tyres of vehicles have grooves (treads)?