The blame has been pinned, squarely and often, on inadequate oversight of U.S. financial institutions, which created ever more complex and risky mortgage instruments, lured people to buy homes they could not afford, and brought the economy crashing to the ground.
Motion on the Earth does not take place in a vacuum. When one thing moves, it moves through or across another. When a wheel turns on an axle, the two surfaces rub against one another. This is called dry friction. Grease can be used to separate the solid metal parts, but this just reduces the problem to layers within the grease sliding past one another.
The friction is acting opposite to the ball rolling in the ground. Friction is a force that resists motion. It always acts in the opposite direction to the motion. Friction is caused by bumps on the two surfaces(whic are in contact), rubbing as they slide across each other. Friction means that objects slow down and lose kinetic energy.