Question

Охотник стреляет с легкой надувной лодки. какую скорость приобретает лодка в момент выстрела, если масса охотника 70 кг, масса дроби 35 г и средняя начальная скорость дробинок равна 320м/с? ствол ружья во время выстрела образует с горизонтом угол 60°

Answer 1

Дано: 
m2 = 70кг;
 m1 = 35 = 3,5 ⋅ 10^-2кг;
v1 = 320м/с;
α = 60°;
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V2 -?
По закону сохранению импульса, имеем уравнение
$0=m_2v_2\cdot\cos \alpha -m_1v_1 \\ \\ v_2= \dfrac{m_2v_2\cdot\cos60а}{m_1} = \dfrac{0.035\cdot320\cdot0.5}{70} =0.08\,\, m/s$

Ответ: 0,08 м/с

Answer 2

Calculation of the Boat's Velocity

To calculate the velocity of the boat at the moment of the shot, we can use the principle of conservation of momentum. The total momentum before the shot is equal to the total momentum after the shot.

The momentum of an object is given by the product of its mass and velocity. In this case, we have the mass of the hunter, the mass of the shot, and the average initial velocity of the shot.

Let's denote the mass of the hunter as m1 (70 kg), the mass of the shot as m2 (35 g = 0.035 kg), and the average initial velocity of the shot as v2 (320 m/s).

Before the shot, the boat is at rest, so its initial velocity is 0 m/s. After the shot, the boat and the shot move together with a common velocity, which we'll denote as v.

According to the conservation of momentum, the total momentum before the shot is equal to the total momentum after the shot:

m1 * 0 + m2 * 0 = (m1 + m2) * v

Simplifying the equation, we get:

0 = (m1 + m2) * v

Solving for v, we find:

v = 0 / (m1 + m2)

Since the denominator is the sum of the masses, we can substitute the given values:

v = 0 / (70 kg + 0.035 kg)

Calculating the result, we find that the velocity of the boat at the moment of the shot is 0 m/s.

Please note that the calculation assumes an idealized scenario where there are no external forces acting on the boat and no energy losses during the shot.