Brownian motion provides key experimental evidence for the kinetic model of matter.
(i) Describe a common laboratory demonstration that can be used to observe Brownian motion.
(ii) Explain how the observations from this demonstration provide evidence that gases or liquids consist of microscopic, rapidly moving particles.
Using the kinetic theory of gases, explain how gas molecules inside a sealed vessel exert a force on its walls, thereby producing pressure.
A heavy-duty transport truck uses pneumatic suspension bellows. The air inside a single bellows unit is at a pressure of 560 kPa560\text{ kPa}560 kPa and supports a portion of the truck's weight. The flat contact area between the bellows and its metal piston plate is 0.035 m20.035\text{ m}^20.035 m2.
(i) State the equation linking pressure, force, and area.
(ii) Calculate the force exerted by the air bellows on the piston plate.
(iii) During a long journey on a hot day, the air inside the bellows warms up significantly. Explain how this increase in temperature would affect the contact area between the bellows and the piston plate, assuming the volume of the bellows and the load (force) supported by it remain constant.
