I'll assume that the chair has four legs.
Since the chair weights 3.7 kg by itself, it will weigh (79+3.7)=82.7 kg with the person sitting on it. And each of the chair's legs will take about (82.7/4)=20.675 kg.
Each leg touches the floor in a circle with 1.3cm diameter. The area of that circle is about (3.14*(1.3/2)^2)=1.327 cm^2.
Pressure is measured by force per area. So, the pressure from each leg is about 20.675kg / 1.327cm^2. That simplifies to 15.58 kg/cm^2.
Answer:
Inertia is the tendency of all objects to resist any change in motion. Inertia causes a moving object to stay in motion at the same velocity (speed and direction) unless a force acts on it to change its speed or direction. It also causes an object at rest to stay at rest.
The magma in the wake the core
Yup, I think you add all of them