Question

4. Визначте потенціальну та кінетичну енергії тіла масою 200 г, кинутого вертикально вгору зі швидкістю 25 м/с, через 2 с від початку руху.

Answer 1

Ответ: експрес доставка

Для визначення потенціальної та кінетичної енергій тіла використаємо формули:

Потенціальна енергія: Ep = mgh

Кінетична енергія: Ek = (1/2)mv^2

де m - маса тіла, g - прискорення вільного падіння, h - висота, на якій знаходиться тіло, v - швидкість тіла.

За умовою задачі, маса тіла m = 200 г = 0.2 кг, швидкість тіла v = 25 м/с, час руху t = 2 с.

Прискорення вільного падіння на Землі приймається за g = 9.81 м/с^2.

Знайдемо висоту, на якій знаходиться тіло через 2 секунди від початку руху:

h = (1/2)gt^2 = (1/2) * 9.81 * 2^2 = 19.62 м

Отже, на висоті 19.62 м в момент часу t = 2 с тіло має потенціальну енергію:

Ep = mgh = 0.2 * 9.81 * 19.62 = 38.4 Дж

Щоб знайти кінетичну енергію тіла, використаємо формулу:

Ek = (1/2)mv^2 = (1/2) * 0.2 * 25^2 = 31.25 Дж

Отже, на висоті 19.62 м в момент часу t = 2 с тіло має потенціальну енергію 38.4 Дж і кінетичну енергію 31.25 Дж.

Объяснение:

Answer 2

Potential and Kinetic Energy of an Object Thrown Vertically Upwards

When an object is thrown vertically upwards, it possesses both potential energy and kinetic energy at different points during its motion.

Potential Energy is the energy possessed by an object due to its position or state. In the case of an object thrown vertically upwards, the potential energy is maximum at the initial point of release and decreases as the object moves higher. At the highest point of its trajectory, the potential energy is at its minimum.

Kinetic Energy is the energy possessed by an object due to its motion. In the case of an object thrown vertically upwards, the kinetic energy is minimum at the initial point of release and increases as the object moves higher. At the highest point of its trajectory, the kinetic energy is maximum.

To calculate the potential and kinetic energy of the object at a specific time, we need to know its mass, velocity, and height.

Given: - Mass of the object (m) = 200 g = 0.2 kg - Initial velocity (u) = 25 m/s - Time (t) = 2 s

Calculating Potential Energy

The potential energy (PE) of an object can be calculated using the formula:

PE = mgh

where: - m is the mass of the object - g is the acceleration due to gravity (approximately 9.8 m/s^2) - h is the height of the object above a reference point

Since the object is thrown vertically upwards, the height at any given time can be calculated using the formula:

h = ut - (1/2)gt^2

Substituting the given values into the formula, we can calculate the height at t = 2 s:

h = (25 m/s)(2 s) - (1/2)(9.8 m/s^2)(2 s)^2

Simplifying the equation gives:

h = 50 m - 19.6 m = 30.4 m

Now we can calculate the potential energy at t = 2 s:

PE = (0.2 kg)(9.8 m/s^2)(30.4 m) = 59.584 J

Therefore, the potential energy of the object at t = 2 s is approximately 59.584 Joules.

Calculating Kinetic Energy

The kinetic energy (KE) of an object can be calculated using the formula:

KE = (1/2)mv^2

where: - m is the mass of the object - v is the velocity of the object

Substituting the given values into the formula, we can calculate the kinetic energy at t = 2 s:

KE = (1/2)(0.2 kg)(25 m/s)^2 = 62.5 J

Therefore, the kinetic energy of the object at t = 2 s is approximately 62.5 Joules.

To summarize: - The potential energy of the object at t = 2 s is approximately 59.584 Joules. - The kinetic energy of the object at t = 2 s is approximately 62.5 Joules.

Please note that these calculations assume no energy losses due to air resistance or other factors.