You pull with a force of 77 n on a piece of luggage of mass 23 kg, but it does
not move. if the coefficient of friction between the luggage and the floor is
0.8, what is the force of static friction acting on the luggage?

The force of static friction acting on the luggage is, Fₓ = 180.32 N

Explanation:

Given data,

The mass of the luggage, m = 23 kg

You pulled the luggage with a force of, F = 77 N

The coefficient of static friction of luggage and floor, μₓ = 0.8

The formula for static frictional force is,

                                      Fₓ = μₓ · η

Where,

                                  η - normal force acting on the luggage 'mg'

Substituting the values in the above equation,

                                   Fₓ = 0.8 x 23 x 9.8

                                        = 180.32 N

Hence, the minimum force require to pull the luggage is, Fₓ = 180.32 N

184N

Explanation:

Frictional force is defined as a force of opposition. This force opposes the moving force. The body placed on a plane surface has a frictional force proportional to the normal reaction force acting on the body.

Mathematically, Ff = nR where;

Ff is the frictional force

n is the coefficient of static friction between the luggage and the floor.

R is the normal reaction which is equal to the weight (W) of the body.

W = mg

Weight = 23×10 = 230N

Since weight = normal reaction

Normal reaction = 230N

coefficient of friction between the luggage and the floor = 0.8

Frictional force (Ff) = 0.8×230

Frictional force = 184N

Therefore, the force of static friction acting on the luggage is 184N

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia