Question

Шарик массой 200 г падает с высоты 20 м с начальной скоростью, равной нулю. Его кинетическая энергия в момент перед ударом о землю равна 35 Дж. Какова потеря механической энергии шарика за счёт сопротивления воздуха?

Answer 1

Ответ:

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Answer 2

Calculation of Potential Energy and Kinetic Energy

To calculate the mechanical energy loss of the ball due to air resistance, we first need to determine the initial potential energy and final kinetic energy of the ball.

The potential energy (PE) of an object is given by the formula:

PE = mgh

where: - m is the mass of the ball (200 g or 0.2 kg), - g is the acceleration due to gravity (approximately 9.8 m/s^2), - h is the height from which the ball is dropped (20 m).

Substituting the given values into the formula, we can calculate the potential energy:

PE = (0.2 kg) * (9.8 m/s^2) * (20 m) = 39.2 J.

Since the ball starts with an initial velocity of zero, its initial kinetic energy (KE) is also zero.

Calculation of Mechanical Energy Loss

The mechanical energy loss of the ball due to air resistance can be calculated by subtracting the final kinetic energy from the initial potential energy.

Given that the kinetic energy of the ball just before impact is 35 J, we can calculate the mechanical energy loss:

Mechanical Energy Loss = PE - KE = 39.2 J - 35 J = 4.2 J.

Therefore, the mechanical energy loss of the ball due to air resistance is 4.2 J.

Please note that this calculation assumes that the only form of energy loss is due to air resistance. Other factors, such as friction with the ground, are not considered in this calculation.

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