If an object on a horizontal frictionless surface is attached to a spring, displaced, and then released, it will oscillate. It is displaced a distance 0.120 mm from its equilibrium position and released with zero initial speed, then after a time 0.790 ss its displacement is found to be a distance 0.120 mm on the opposite side, and it has passed the equilibrium position once during this interval. Find the amplitude of the motion.

=m

Find the period of the motion.

=s

Find the frequency of the motion.

=Hz

a.0.120mm

b.1.58s

c.0.6329Hz

Explanation:

a. Given that 0.120mm is displaced from equilibrium, 0.120mm after 0.790s on opposite side:

-The amplitude is the maximum displacement from equilibrium.

-The object goes from x=+A to x=-A and back during one cycle.

#Hence, the amplitude of the motion is 0.120mm

b.Motion from maximum positive displacement to maximum negative displacement takes places during half the period of Simple Harmonic Motion(SHM)

#Hence, the period of the motion is 1.58s

c. Frequency is calculated as one divided by the period of the motion.

From b above we know that the motions period is 1.58s

Therefore:

Frequency=1/period=1/1.58=0.6329Hz

#The frequency of the motion is 0.6329Hz

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