A bullet with mass 0.40 kg is fired with an initial velocity of 400 m/s from a gun with mass 5.0 kg. The speed of the recoil of the gun is

Massgun*velocitygun+massbullet*veloictybullet=0

solve for veloictygun

32m/s

To find the speed of the recoil of the gun, we can use the principle of conservation of momentum.

According to the principle of conservation of momentum, the total momentum before firing the gun is equal to the total momentum after firing the gun.

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

The momentum before firing the gun is the sum of the momentum of the bullet and the gun. The momentum after firing the gun is the sum of the momentum of the bullet and the recoil of the gun.

Let's denote the initial velocity of the bullet as Vb, the mass of the bullet as Mb, the initial velocity of the gun as Vg, and the mass of the gun as Mg.

Given:
Mb = 0.40 kg (bullet mass)
Vb = 400 m/s (initial velocity of the bullet)
Mg = 5.0 kg (gun mass)

According to the conservation of momentum:
Mb * Vb + Mg * Vg = Mb * Vbullet + Mg * Vrecoil

We know the bullet is fired forward with the given initial velocity. Considering the gun as a closed system (no external forces), the momentum of the system after firing will be zero.

Therefore, the calculation can be simplified to:
Mg * Vg = - Mb * Vb

Substituting the given values:
5.0 kg * Vg = - 0.40 kg * 400 m/s

Solving for Vg:
Vg = (- 0.40 kg * 400 m/s) / 5.0 kg

Vg = - 32 m/s

Therefore, the speed of the recoil of the gun is 32 m/s. Note that the negative sign indicates that the recoil is in the opposite direction of the bullet's initial velocity.

To find the speed of the recoil of the gun, we can use the principle of conservation of momentum. According to this principle, the total momentum before an event is equal to the total momentum after the event, provided no external forces act on the system.

In this scenario, the bullet and the gun are part of the same system. The momentum before the gun is fired is zero since both the bullet and the gun are at rest. After the gun is fired, the bullet and the gun move in opposite directions with different velocities. Let's denote the velocity of the bullet as Vbullet and the velocity of the gun as Vgun.

Using the principle of conservation of momentum, we can write:

(Initial momentum) = (Final momentum)

(0) = (mass of bullet x velocity of bullet) + (mass of gun x velocity of gun)

Since the velocity of the bullet is given as 400 m/s, the mass of the bullet is 0.40 kg, and the mass of the gun is 5.0 kg, we can substitute these values into the equation:

0 = (0.40 kg x 400 m/s) + (5.0 kg x Vgun)

Simplifying the equation, we get:

0 = 160 kg·m/s + 5.0 kg x Vgun

Rearranging the equation to solve for Vgun, we have:

5.0 kg x Vgun = -160 kg·m/s

Dividing both sides of the equation by 5.0 kg, we find:

Vgun = -160 kg·m/s / 5.0 kg

Vgun = -32 m/s

Therefore, the speed of the recoil of the gun is 32 m/s. The negative sign indicates that the direction of the recoil is opposite to the direction of the bullet.