Question

Шарик массой 0,2кг, подвешен на нити длинной 1м, отвели от положения равновесия и отпустили. Скорость шарика в нижней точке 0,6м/с. Какова сила натяжения нити в этот момент?

Answer 1

Так-с. Шарик движется по дуге окружности, значит его ускорение в нижней точке будет направлено вверх и равняться оно будет v^2/L = 0.36м/с^2

На шарик в нижней точке действуют две силы - тяжести (вниз) и натяжения нити(вверх). Запишем 2 Закон Ньютона

ma = -mg+T
T = m(a+g) = 0.2*(0.36+9.81) = 2.03 Н

Ответ - 2.03 Н

Answer 2

Calculation of Tension Force in the String

To calculate the tension force in the string when the ball is at the bottom point, we can use the principle of conservation of mechanical energy. At the bottom point, the ball has maximum kinetic energy and zero potential energy. The total mechanical energy is conserved, so we can equate the initial potential energy to the final kinetic energy.

The potential energy at the initial position is given by the formula:

Potential Energy = mass x gravity x height

The kinetic energy at the final position is given by the formula:

Kinetic Energy = (1/2) x mass x velocity^2

Since the ball is at the bottom point, the height is zero. Therefore, the potential energy at the initial position is also zero.

Using the given values: - Mass of the ball (m) = 0.2 kg - Height (h) = 1 m - Velocity (v) = 0.6 m/s

We can calculate the tension force in the string at the bottom point.

Calculation:

Potential Energy at the initial position = 0 Kinetic Energy at the final position = (1/2) x mass x velocity^2

0 = (1/2) x 0.2 kg x (0.6 m/s)^2

Simplifying the equation:

0 = (1/2) x 0.2 kg x 0.36 m^2/s^2

0 = 0.036 kg m^2/s^2

Since the potential energy is zero, the tension force in the string at the bottom point is also zero.

Therefore, the tension force in the string at the moment when the ball is at the bottom point is zero.

Please note that the calculation assumes ideal conditions, neglecting any air resistance or other external forces that may affect the motion of the ball.