Abarbell is 1.5 m long. three weights, each of mass 20 kg, are hung on the left and two weights of the same mass, on the right. the width of each weight is 4 cm and each group of weights is placed 4 cm from the ends. where is the center of mass of the barbell as measured from the mid-point, m, of the bar? the bar is of uniform mass and has mass 5 kg, and the retaining collars are of negligible mass. take to the right as positivea. -5.90cmb. -11.6cmc. +13.7cmd. +5.90cme. none of the above

b. -11.6 cm

Explanation:

We have given parameters:

Length, l = 1.5 m = 150 cm

Mass of weight, = 20 kg

Width, x = 4 cm

Distance d = 4 cm

Mass of bar, = 5 kg

We are asked to find the center of mass from the mid-point,

Since 3 weights are on the left and 2 weights are on the right, we know:

= 3 * 20 = 60 kg

= 2 * 20 = 40 kg

And also we know that, = 150/2 = 75 cm

For the left side, center of mass is:

cm

From the midpoint, the distance to the left is:

cm

For the right side, center of mass is:

cm

From the midpoint, the distance to the right will be:

cm

Hence,

cm

b) phosphorus pentoxide

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