What is the definition of friction?

Several mountains together form a mountain . a few of these combined form a mountain system. several systems combined form a mountain , which can stretch thousands of miles in length.

Determine el momento angular de un rueda de 3000g moviendose a 10m/s con un radio de giro de 400cm

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.