Question

Помогите очень срочно!!!!!!! 1) Людина масою 60 кг, яка бігла зі швидкістю 4 м/с , стрибнула в нерухомий візок. Визначте масу візка,, якщо він почав рухатися зі швидкістю 1 м/с ? 2) Тіло, яке підкинули вертикально вгору зі швидкістю 20 м/с , піднялося на висоту 14 м. Визначте скільки відсотків механічної енергії перейшло у внутрішню енергію.

Answer 1

Ответ:

см фото

Объяснение:

Answer 2

Calculation of the Mass of the Cart

To determine the mass of the cart, we can use the principle of conservation of momentum. According to this principle, the total momentum before the collision is equal to the total momentum after the collision.

Given: - Mass of the person (m1) = 60 kg - Initial velocity of the person (v1) = 4 m/s - Initial velocity of the cart (v2) = 0 m/s (since it is stationary) - Final velocity of the person and the cart (v3) = 1 m/s

Using the conservation of momentum equation:

(m1 * v1) + (m2 * v2) = (m1 * v3) + (m2 * v3)

Substituting the given values:

(60 kg * 4 m/s) + (m2 * 0 m/s) = (60 kg * 1 m/s) + (m2 * 1 m/s)

240 kg·m/s = 60 kg·m/s + m2 kg·m/s

Subtracting 60 kg·m/s from both sides:

180 kg·m/s = m2 kg·m/s

Therefore, the mass of the cart (m2) is 180 kg.

Calculation of the Percentage of Mechanical Energy Converted to Internal Energy

To determine the percentage of mechanical energy converted to internal energy, we need to calculate the initial mechanical energy and the final internal energy.

Given: - Initial velocity of the object (v1) = 20 m/s - Height reached by the object (h) = 14 m

The initial mechanical energy (E1) is given by the formula:

E1 = (1/2) * m * v1^2

where m is the mass of the object.

The final internal energy (E2) is given by the formula:

E2 = m * g * h

where g is the acceleration due to gravity (approximately 9.8 m/s^2).

To calculate the percentage of mechanical energy converted to internal energy, we can use the formula:

Percentage = (E2 / E1) * 100

Substituting the given values:

E1 = (1/2) * m * (20 m/s)^2 E2 = m * 9.8 m/s^2 * 14 m

Simplifying the equations:

E1 = 200 m E2 = 137.2 m

Percentage = (137.2 m / 200 m) * 100

Therefore, the percentage of mechanical energy converted to internal energy is approximately 68.6%.