sure of the carbon dioxide inside the bottle is 1.80 x 10' Pa. Assuming that the top and bottom surfaces of the cap each have an area of 4.10 x 10- m, obtain the magnitude of the force that the screw thread exerts on the cap in order to keep it on the bottle. The air pressure outside the bottle is one atmosphere. 15. M A 75-kg skier is going down a slope oriented 420 above the horizon- tal. The area of each ski in contact with the snow is 0.15 m2. Determine the pressure that each ski exerts on the snow. 16. M A suitcase (mass m = 20 kg) is resting on the floor of an elevator. The part of the suitcase in contact with the floor measures 0.60 m x 0.20 m. The elevator is moving upward with an acceleration of magnitude 2.2 m/s. * What pressure (in excess of atmospheric pressure) is applied to the floor beneath the suitcase? 17. M CHALK A cylinder is fitted with a piston, 2 beneath which is a spring, as in the drawing. The cylinder a is open to the air at the top. Friction is absent. The spring constant of the spring is 3600 N/m. The piston has a neg- ligible mass and a radius of 0.024 m. (a) When the air beneath the piston is completely pumped out, how much does the atmospheric pressure cause the spring to com