A heavy tractor tyre rests on soft ground. The tyre exerts a pressure on the ground of 140 kPa.
The area of the tyre in contact with the ground is 0.045 m2.
State the equation linking pressure, force, and area.
Calculate the force exerted on the ground by the tyre. Give the unit.
Use ideas about molecules to explain why the air inside the inflated tractor tyre exerts pressure on the inside walls of the tyre.
Additional air is pumped into the tyre to inflate it further. This increases both the number of molecules and the temperature of the air inside the tyre. Use ideas about molecules to explain why the air pressure inside the tyre increases.