(a) The amount of useful energy produced can be calculated using the formula for gravitational potential energy, which is mass (m) times gravity (g) times height (h). In this case, m = 1250 kg, g = 9.8 m/s^2 (approximate value of gravity on Earth), and h = 1.8 m. So, the useful energy is:

E = m * g * h = 1250 kg * 9.8 m/s^2 * 1.8 m = 22050 J = 22 kJ

(b) The amount of energy used to pull the car from the ditch can be calculated using the formula for work done, which is force (F) times distance (d). In this case, F = 5500 N and d = 12.6 m. So, the energy used is:

W = F * d = 5500 N * 12.6 m = 69300 J = 69 kJ

(c) The efficiency of the process can be calculated as the ratio of useful energy produced to the total energy used, multiplied by 100 to get a percentage. So, the efficiency is:

Efficiency = (Useful energy / Total energy) * 100 = (22 kJ / 69 kJ) * 100 = 31.88% ≈ 32%

The efficiency is less than 100% because not all of the energy used to pull the car out of the ditch is converted into useful energy. Some of the energy is lost as heat due to friction between the car and the ground, and between the cable and the car. This is a fundamental principle of physics known as the second law of thermodynamics, which states that energy conversions are never 100% efficient.

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(a) The amount of useful energy produced can be calculated using the formula for gravitational potential energy, which is mass (m) times gravity (g) times height (h). In this case, m = 1250 kg, g = 9.8 m/s^2 (approximate value of gravity on Earth), and h = 1.8 m. So, the useful energy is:

E = m * g * h = 1250 kg * 9.8 m/s^2 * 1.8 m = 22050 J = 22 kJ

(b) The amount of energy used to pull the car from the ditch can be calculated using the formula for work done, which is force (F) times distance (d). In this case, F = 5500 N and d = 12.6 m. So, the energy used is:

W = F * d = 5500 N * 12.6 m = 69300 J = 69 kJ

(c) The efficiency of the process can be calculated as the ratio of useful energy produced to the total energy used, multiplied by 100 to get a percentage. So, the efficiency is:

Efficiency = (Useful energy / Total energy) * 100 = (22 kJ / 69 kJ) * 100 = 31.88% ≈ 32%

The efficiency is less than 100% because not all of the energy used to pull the car out of the ditch is converted into useful energy. Some of the energy is lost as heat due to friction between the car and the ground, and between the cable and the car. This is a fundamental principle of physics known as the second law of thermodynamics, which states that energy conversions are never 100% efficient.

Knowee AI · Accepted Answer

(a) The amount of useful energy produced can be calculated using the formula for gravitational potential energy, which is mass (m) times gravity (g) times height (h). In this case, m = 1250 kg, g = 9.8 m/s^2 (approximate value of gravity on Earth), and h = 1.8 m. So, the useful energy is:

E = m * g * h = 1250 kg * 9.8 m/s^2 * 1.8 m = 22050 J = 22 kJ

(b) The amount of energy used to pull the car from the ditch can be calculated using the formula for work done, which is force (F) times distance (d). In this case, F = 5500 N and d = 12.6 m. So, the energy used is:

W = F * d = 5500 N * 12.6 m = 69300 J = 69 kJ

(c) The efficiency of the process can be calculated as the ratio of useful energy produced to the total energy used, multiplied by 100 to get a percentage. So, the efficiency is:

Efficiency = (Useful energy / Total energy) * 100 = (22 kJ / 69 kJ) * 100 = 31.88% ≈ 32%

The efficiency is less than 100% because not all of the energy used to pull the car out of the ditch is converted into useful energy. Some of the energy is lost as heat due to friction between the car and the ground, and between the cable and the car. This is a fundamental principle of physics known as the second law of thermodynamics, which states that energy conversions are never 100% efficient.

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