A body of mass 100g moving with a velocity of 10m/s collides with a wall. If after the collision it moves in an opposite direction, calculate the change in Momentum

1 answer

To calculate the change in momentum of the body when it collides with the wall, we will first find the initial and final momentum.

  1. Initial momentum (\( p_i \)): \[ p_i = m \cdot v_i \] Where:

    • \( m = 100 , \text{g} = 0.1 , \text{kg} \) (converting grams to kilograms)
    • \( v_i = 10 , \text{m/s} \) (initial velocity)

    \[ p_i = 0.1 , \text{kg} \cdot 10 , \text{m/s} = 1 , \text{kg m/s} \]

  2. Final momentum (\( p_f \)): After colliding with the wall, the body moves in the opposite direction. Therefore, its final velocity will be: \[ v_f = -10 , \text{m/s} \]

    Calculating the final momentum: \[ p_f = m \cdot v_f = 0.1 , \text{kg} \cdot (-10 , \text{m/s}) = -1 , \text{kg m/s} \]

  3. Change in momentum (\( \Delta p \)): \[ \Delta p = p_f - p_i \] \[ \Delta p = -1 , \text{kg m/s} - 1 , \text{kg m/s} = -2 , \text{kg m/s} \]

Thus, the change in momentum is: \[ \Delta p = -2 , \text{kg m/s} \]

The negative sign indicates that the momentum has changed direction. The magnitude of the change in momentum is \( 2 , \text{kg m/s} \).