A piece of iron block moves across a rough horizontal surface before coming to rest. The mass of the block is 1.3 kg, and its initial speed is 4.0 m/s. How much does the block's temperature increase, if it absorbs 71% of its initial kinetic energy as internal energy? The specific heat of iron is 452 J/(kg · °C).

0.0126°C

Explanation:

Kinetic energy sustain by the block,K.E = 1/2× mass×velocity^2

K.E = 1/2 ×1.3×(4^2)

=1/2 × 1.3× 16 = 1.3 ×8 = 10.4J

The internal energy is 71% of kinetic energy is;

U= 71/100 × 10.4 = 7.38J

But U = m × C × ∆T

Where U is internal energy

m is the mass of iron

C is the heat capacity of iron

∆T is the temperature change

By make ∆T the subject of the formula we have

∆T=U/ m×C

=7.38/ 1.3×452= 0.0126°C

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

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