Aperson with mass m stands on a ladder of mass m that leans against a frictionless vertical wall and makes an angle of 53° measured from the horizontal. the ladder does not slip on the horizontal surface due to a static frictional force between the ladder and the ground. some of the forces exerted on the ladder can produce torques on the ladder. using the contact point between the ladder and the ground as a reference, which force(s) exerted on the ladder produce clockwise torques?

clockwise torque is due to weight of the person + weight of the ladder

Explanation:

As we know that the forces that act on the ladder is given as

1) friction force

2) Normal force at the ends of the ladder

3) Weight of the person standing on the ladder

4) Weight of the ladder

So here we know that our reference point is at the bottom position of the ladder

So we will have

Torque due to weight of the person and weight of the ladder is counter balanced by the torque due to normal force and torque due to friction force

So here we have

clockwise torque is due to weight of the person + weight of the ladder

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