Question

Деревянный брусок массой 2 кг первоначально покоится на абсолютно гладкой горизонтальной поверхности. В брусок попадает и застревает в нем пуля массой 5 г, летевшая со скоростью 500 м/с. С какой скоростью станет двигаться брусок с пулей после соударения?

Answer 1

Закон сохранения импульса p1+p2=P p1=0(тк начальная скорость бруска равна 0) p2=0,005*500=2,5 p=(m+M)*v=2,5 2,005*v=2,5 v=1,25м/с

Answer 2

Problem Analysis

We are given a wooden block with a mass of 2 kg initially at rest on a smooth horizontal surface. A bullet with a mass of 5 g and a velocity of 500 m/s gets embedded in the block. We need to determine the velocity of the block with the bullet after the collision.

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. Therefore, the initial momentum of the block and the bullet is given by:

Initial momentum = (mass of block) * (velocity of block) + (mass of bullet) * (velocity of bullet)

After the collision, the bullet gets embedded in the block, so they move together as a single system. Let's assume the final velocity of the block with the bullet is v. The mass of the block with the bullet is the sum of the mass of the block and the mass of the bullet.

Mass of block with bullet = mass of block + mass of bullet

The final momentum of the block with the bullet is given by:

Final momentum = (mass of block with bullet) * (final velocity)

According to the principle of conservation of momentum, the initial momentum is equal to the final momentum:

Initial momentum = Final momentum

Substituting the values into the equation and solving for the final velocity, we can find the answer.

Calculation

Let's calculate the final velocity of the block with the bullet after the collision.

Initial momentum = (mass of block) * (velocity of block) + (mass of bullet) * (velocity of bullet)

Final momentum = (mass of block with bullet) * (final velocity)

Initial momentum = Final momentum

Substituting the given values:

Initial momentum = (2 kg) * (0 m/s) + (0.005 kg) * (500 m/s)

Final momentum = (2 kg + 0.005 kg) * (final velocity)

Initial momentum = Final momentum

Simplifying the equation:

0 = (2.005 kg) * (final velocity)

Solving for the final velocity:

final velocity = 0 m/s

Answer

After the collision, the block with the embedded bullet will come to rest. Therefore, the final velocity of the block with the bullet is 0 m/s.