contestada

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 ebea and ecea What do these ratios tell you about the conservation of energy A is t class=

Respuesta :

akiran007

Answer:

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.

onyebuchinnaji

(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.

(c) mechanical energy is conserved between a and b.

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

The given parameters;

  • mechanical energy at A, [tex]E_a = 2,940 \ J[/tex]
  • mechanical energy at B, [tex]E_b =1,058.3 \ J[/tex]
  • mechanical energy at C, [tex]E_c = 0[/tex]

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

[tex]ratio = \frac{E_b}{E_a} = \frac{1058.3}{2940} = 0.36[/tex]

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

[tex]ratio = \frac{E_c}{E_a} = \frac{0}{2940} = 0[/tex]

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

[tex]\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[/tex]

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;

[tex]\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[/tex]

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

Learn more here:https://brainly.com/question/19969393

Otras preguntas