Physics, 26.10.2020 09:00 sandyrose935

Calculate the ratio of the mechanical energy at B and mechanical energy at a (eb, ea) and (ec, ea). What do these ratios tell you about the conservation of energy? A) is the mechanical conserved between a and b? explain

B) is the mechanical energy conserved between b and c ?explain

Calculate the ratio of the mechanical energy at B and mechanical energy at a (eb,ea) and (ec,ea). W

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Answer from: wickedskatboarder

(a) The ratio of the mechanical energy at B and mechanical energy at A is 0.36.

(b) The ratio of the mechanical energy at C and mechanical energy at A is 0.

(d) mechanical energy is not conserved between b and c.

The given parameters;

mechanical energy at A, $E_a = 2,940 \ J$ mechanical energy at B, $E_b =1,058.3 \ J$ mechanical energy at C, E_c = 0

The ratio of the mechanical energy at B and mechanical energy at A;

$ratio = \frac{E_b}{E_a} = \frac{1058.3}{2940} = 0.36$

The ratio of the mechanical energy at C and mechanical energy at A;

$ratio = \frac{E_c}{E_a} = \frac{0}{2940} = 0$

The change mechanical energy between A and B from the given position;

$\Delta E = mg(h_b - h_a) - \frac{1}{2}m(v_b^2 - v_a^2)\\\\ \Delta E = 50\times 9.8(2-6) \ - \ \frac{1}{2} \times 50(8.85^2 - 0)\\\\\Delta E =- 1960 + 1960\\\\\Delta E = 0 \ J$

Thus, we can conclude that mechanical energy is conserved between a and b.

The change mechanical energy between A and B from the given position;

$\Delta E = mg(h_c - h_b) - \frac{1}{2}m(v_c^2 - v_b^2)\\\\ \Delta E = 50\times 9.8(0-2) \ - \ \frac{1}{2} \times 50(0^2 - 8.85^2)\\\\\Delta E = -980 + 1960 \\\\\Delta E = 980 \ J$

Thus, we can conclude that mechanical energy is not conserved between b and c.

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Answer from: arivalen

Yes at A the mechanical energy is conserved.

Yes at B the part of mechanical energy is conserved potential energy and kinetic energy and some is lost as frictional force.

Explanation:

Ratio = Eb/ Ea= 1058.3 J/2940 J= 0.3599

Ratio = Ec/ Eb= 0J/ 1058.3 J= 0

At point A the skater is at rest or it is the starting point and the whole energy is due to the position of the skater i.e= mgh = 50 *9.8*6= 2940 J

Since there's no movement there is no Kinetic energy = 0 J

Yes at A the mechanical energy is conserved.

At point B the skater has traveled for some of the distance . It has potential energy and kinetic energy.

Yes at B the part of mechanical energy is conserved as potential energy and kinetic energy.

The total Mechanical energy = 1058.3 J

At point B Total Mechanical energy = PE+ KE

1058.3J = 980 J + 78.3 J

1058.3 J = mgh + 1/2mv²

= 50*2*9.8 + 1/2 *50*(8.85)²

= 980 J + 78.3 J

As the total energy of the system must remain the same some of the mechanical energy is lost as frictional force at point B .

2940 J-1058.3 J= 1881.7

At Point C the skater has arrived at the end point and the height , speed, PE, KE and ME all are zero.

Answer from: Quest

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

Answer from: Quest

This did i unseated, sorry

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