Given, the Bullet’s mass (m_{1}) = 50 g

The rifle’s mass (m_{2}) = 4 kg = 4000g

Initial velocity of the fired bullet (v_{1}) = 35 m/s

Let the recoil

velocity be v_{2.}

Since the rifle was initially at rest, the initial momentum of the rifle = 0

Total momentum of the rifle and bullet after firing = m_{1}v_{1} + m_{2}v_{2}

As per the law of conservation of momentum, the total momentum of the rifle and the bullet after firing = 0 (same as initial momentum)

Therefore, m_{1}v_{1} + m_{2}v_{2} = 0

_{\(This \,implies \,that\, v_2 = -\frac{m_1v_1}{m_2}\)}

_{\( = -\frac{50g\,\times \, 35ms^{-1}}{4000g}\)}

_{= - 0.4375 m/s}

Therefore, the recoil velocity of the rifle is 0.4375 meters per second in the direction opposite to the trajectory of the bullet (backward direction).

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Time (seconds) |
Distance (meters) |

0 | 0 |

1 | 1 |

2 | 8 |

3 | 27 |

4 | 84 |

5 | 125 |

6 | 216 |

7 | 343 |

**(a)** What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?

**(b)** What do you infer about the forces acting on the object?

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