Question

Пуля массой 0,02 кг, летящая горизонтально со скоростью 700 м/с, попадает в брусок массой 1 кг, стоящий на гладкой горизонтальной поверхности, и пробив его, вылетает со скоростью 400 м/с. Определить с какой скоростью будет двигаться брусок.

Answer 1

Ответ:

U=6 м/с

Объяснение:

m=0,02 кг

V1=700 м/с

V2=400 м/с

M=1 кг    

U=?

По закону сохранения импульса

m*V1=m*V2+M*U ⇒ U=(V1-V2)*m/M=(700-400)*0,02/1=6 м/c

Answer 2

Problem Analysis

We are given the following information: - A bullet with a mass of 0.02 kg is flying horizontally with a velocity of 700 m/s. - The bullet hits a block with a mass of 1 kg, which is initially at rest on a smooth horizontal surface. - After penetrating the block, the bullet exits with a velocity of 400 m/s.

We need to determine the velocity of the block after the bullet passes through it.

Solution

To solve this problem, we can apply 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.

The momentum of an object is given by the product of its mass and velocity: momentum = mass * velocity.

Let's denote the mass of the bullet as m1, the velocity of the bullet before the collision as v1, the mass of the block as m2, and the velocity of the block after the collision as v2.

Before the collision, the total momentum is the sum of the momenta of the bullet and the block: Total momentum before collision = m1 * v1 + m2 * 0 (since the block is initially at rest).

After the collision, the bullet penetrates the block and exits with a velocity of 400 m/s. The block acquires a velocity, which we need to determine.

The total momentum after the collision is the sum of the momenta of the bullet and the block: Total momentum after collision = m1 * 400 + m2 * v2.

Since the total momentum before the collision is equal to the total momentum after the collision, we can set up the following equation: m1 * v1 + m2 * 0 = m1 * 400 + m2 * v2.

We can rearrange this equation to solve for v2: v2 = (m1 * v1 - m2 * 400) / m2.

Now we can substitute the given values into the equation to find the velocity of the block.

Calculation

Given: - Mass of the bullet (m1) = 0.02 kg - Velocity of the bullet before the collision (v1) = 700 m/s - Mass of the block (m2) = 1 kg - Velocity of the bullet after the collision (v2) = 400 m/s

Substituting these values into the equation, we get: v2 = (0.02 * 700 - 1 * 400) / 1.

Simplifying the equation, we have: v2 = (14 - 400) / 1.

Calculating further, we find: v2 = -386 / 1.

Therefore, the velocity of the block after the bullet passes through it is -386 m/s.

Answer

The block will move with a velocity of -386 m/s after the bullet passes through it.

Note: The negative sign indicates that the block is moving in the opposite direction to the bullet's initial velocity.