is friction given by gravity?

Yes, you need gravity to have friction in case of objects on the surface.

Ff = μк mgsinθ

Gravity itself has nothing to do with friction. Directly from Wikipedia: Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. In order for friction to occur, there has to be some kind of matter. And gravity is a force, not matter. Therefore friction is not caused by gravity.

In part, yes in most cases. [See source.] In most day to day cases, friction force F = kmg; where k is a coefficient, m is the mass of whatever is rubbing a surface, and g, ta da, is the gravity field.

As you can see, with a bigger g value and all other things equal, there will be greater friction force. It will also increase with greater k and/or greater mass, m. But gravity, as you surmised, is a major player.

Friction means rubbing together. We have it because surfaces, even seemingly smooth surfaces, are rough and irregular at the microscopic level. So the roughnesses rub together and impede each surface from moving. And that's the force of friction.

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RE:

is friction given by gravity?

how comes that we have friction?

nothing is ever completely smooth, so like when you get two saws together it bocomes difficult to pull them apart, this force is called friction, and it turnes power into heat (rub your hands togetrher fast and hard). it isn't caused by gravity, nor is it related in any way. if friction didn't exist in space then how is it possible to walk on the moon??. That very action proves that there is friction. this is backed up by Issac Newton's third law of physics

no gravity is not related with friction, friction is created by ground mostly it is an external force which opposes the force applied object and tries to stop it or pushes in the opposite direction it is the reaction stated by newton for action of force. it is normally denoted as negative force it can be caused by various objects such as surface(ground) e.t.c

Gravity creates friction. That is why in space there is no friction.