How is fluid rolling sliding and static friction increased?

Answer 1

The resistive forces of each of those types of friction except for fluid friction depend on both the normal force (exerted on the object by the surface that it's on) and the friction coefficient that corresponds to that type of friction. So naturally we'd increase the force of friction by increasing either or both of those factors. The friction coefficent can be increased by making the surfaces "rougher" so that more of the energy is lost by being turned into heat and/or sound.

We can also increase the normal force to increase the force of friction. The most straightforward way is to make the object heavier so that the supporting surface pushes harder against the object, increasing the force of friction. It's important to know that the the normal force decreases when the surface becomes increasingly slanted. For example, an object dropped against a wall is not being held up by the surface at all so there's no normal force. So we can increase the force of friction by making sure that the surface is completely parallel to the ground. That way, the surface is supporting the entire force due to gravity acting on the object. We can also be extreme by changing the "apparent weight" of the object. If the object is on a surface that's accelerating upwards (like an elevator), the force of friction will be higher than normal because the surface will be pushing even harder against the object.

For each of the individual friction types, there are some differences. Sliding and static friction are similar to each other. On the other hand, rolling friction often depends on internal friction in the wheel bearings. That's why bearings often use balls to minimize contact area and are well-lubricated. Fluid friction increases with velocity and depends on how viscous the fluid is. The exact relationship between velocity and drag depends a lot on the geometry and speed of the object.

Answer 2

Fluid friction is increased by increasing the viscosity of the fluid. Rolling friction is increased by using materials with less elasticity. Sliding friction is increased by increasing the normal force pressing the surfaces together or by using materials with higher coefficients of friction. Static friction is increased by increasing the roughness of the surfaces or by increasing the normal force between the objects.