Answer: Choose the normal force acting between the object and the ground. Let's assume a normal force of 250 N.
Determine the friction coefficient.
Multiply these values by each other: 250 N * 0.13 = 32.5 N .
You just found the force of friction!
Explanation:
Answer:
Pressure, 
Explanation:
It is given that,
Combined mass of the man and the chair, m = 95 kg
Radius of the leg of chair, r = 0.5 cm = 0.005 m
A large man sits on a four-legged chair with his feet off the floor. The force acting per unit area is called the pressure exerted.
Area of 4 legs, A = 4 A
So, the pressure each leg exert on the floor is 
. Hence, this is the required solution.
Answer:
Ptolemy proposed a model, he reference system is centered on the Earth
Copernicus, proposed a deferent system, this system is centered on the Sun, where it is at the origin of the system
Explanation:
Thousands of years ago, Ptolemy proposed a model to explain the movement of the planets and stars in the sky, in this model the reference system is centered on the Earth, so each body is orbiting in different spheres around the Earth as its center, this system had very complicated calculations and curves to be able to explain the orbits of the planets.
More recently Copernicus, proposed a deferent system, this system is centered on the Sun, where it is at the origin of the system, in this system the movement of the planets are ellipses, which is a much simpler explanation and has been widely accepted, in current systems the reference system is fixed in the bodies more massive, since this simplifies the explanation of the movements.
