Question

Шарик массой 100 г падает с высоты 10 м с нулевой начальной скоростью. Сопротивлением воздуха пренебречь. Какова кинетическая энергия шарика в момент падения на землю? Ответ в Дж.

Answer 1

Дано:
m = 100 г = 0,1 кг
h = 10 м
Vo = 0 м/с
_________
Eк - ?

Находим потенциальную энергию шарика перед падением:
Eп = m*g*h = 0,1*10*10 = 10 Дж

По закону сохранения энергии:
Eк = Eп = 10 Дж

Ответ: 10 джоулей

Answer 2

Calculation of Kinetic Energy

To calculate the kinetic energy of the ball at the moment it hits the ground, we can use the formula:

Kinetic Energy (KE) = 1/2 * mass * velocity^2

Given: - Mass of the ball (m) = 100 g = 0.1 kg - Height from which the ball falls (h) = 10 m - Negligible air resistance

First, let's calculate the velocity of the ball just before it hits the ground. We can use the equation of motion:

v^2 = u^2 + 2gh

Where: - v is the final velocity (which is 0 m/s when the ball hits the ground) - u is the initial velocity (which is 0 m/s since the ball starts from rest) - g is the acceleration due to gravity (approximately 9.8 m/s^2) - h is the height from which the ball falls (10 m)

Plugging in the values, we can solve for v:

0^2 = 0^2 + 2 * 9.8 * 10

Simplifying the equation, we get:

0 = 196

Since the equation has no real solutions, it means that the ball hits the ground with a velocity of 0 m/s.

Now, we can calculate the kinetic energy using the formula mentioned earlier:

KE = 1/2 * mass * velocity^2

Substituting the values:

KE = 1/2 * 0.1 * 0^2

Simplifying the equation, we get:

KE = 0 J

Therefore, the kinetic energy of the ball at the moment it hits the ground is 0 Joules.