unlike a block of wood, a ball rolls down a ramp rather than sliding down. why?

one point of surface contact means less friction, and the propensity to roll due to shape.

the block has more surface area touching the ramp, creating friction between the two surfaces.

Rolling friction almost always has a lower coefficient of friction than other types of friction. Thus a force can more easily overcome rolling friction and cause motion. So when a gravitational force is applied to a ball on a ramp, the force will much more easily surpass that of the rolling friction, and so will roll instead of slide.

If you can imagine changing the geometry of the ball (say, by gluing pieces of wood to the outside) such that rolling is much more difficult, you may notice that the same ball will now slide down the ramp before it rolls. Since you've altered the geometry, the coefficient of rolling friction is now greater than the (initally static friction) kinetic friction, and so it slides.

The concept here is that motion will tend toward that of the _smallest_ coefficient of friction. For a ball, that is rolling friction, and for a wood block that is kinetic friction.

For the ball, the horizontal force of ball weight to the inclined surface is greater than friction force so it rolls down, the opposite thing to the wood block.

the ball is circular and as such has less friction then a block of wood,which is flat. block of wood has more surface touching the ramp, causing more friction

silly question, but i guess i'll answer. Because the ball has no edges and no end, so given an angle, and gravity, the gravity pulls the ball as it rolls infinitely, until the ramp ends, or something blocks it.

The ball is able to keep static friction by rolling, static friction is stronger than kenetic friction so it does not slide

the block on the other hand must slide against kenetic friction because it cannot maintain static friction

because on a ball, only one point at a time can touch the ramp. the next point....what would follow next is a series of BS i would say if i were to ever encounter this question on a test.

the way the structures are made, blocks having flat surfaces and a ball having a round surface, self explainable

less surface area touching the ramp. balls roll justbecause.com

Surface area