During a head-on collision between two automobiles, the occupants are decelerated rapidly. Use the idea of impulse to explain why an air bag that quickly inflates front of an occupant reduces the likelihood of injury.

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.