A 0.14 kg baseball is thrown horizontally at 38. m/s and after it is struck by a bat, it travels at -38. m/s. If the contact time of the bat and ball was 0.0006 seconds, what was the average force the bat exerted on the ball?

-17,733 N

-1,733 N

-17.7 N

-12 kg⋅m/s

1 answer

To find the average force exerted by the bat on the baseball, we can use the impulse-momentum theorem, which states that the impulse (change in momentum) is equal to the average force multiplied by the time the force is applied.

  1. Calculate the initial and final momentum of the baseball:

    The initial velocity \( v_i \) of the baseball is \( 38 , \text{m/s} \) (thrown horizontally), and after being struck, the final velocity \( v_f \) is \( -38 , \text{m/s} \) (indicating it is now moving in the opposite direction).

    The mass \( m \) of the baseball is \( 0.14 , \text{kg} \).

    • Initial momentum \( p_i \): \[ p_i = m \times v_i = 0.14 , \text{kg} \times 38 , \text{m/s} = 5.32 , \text{kg⋅m/s} \]

    • Final momentum \( p_f \): \[ p_f = m \times v_f = 0.14 , \text{kg} \times (-38 , \text{m/s}) = -5.32 , \text{kg⋅m/s} \]

  2. Calculate the change in momentum \( \Delta p \): \[ \Delta p = p_f - p_i = -5.32 , \text{kg⋅m/s} - 5.32 , \text{kg⋅m/s} = -10.64 , \text{kg⋅m/s} \]

  3. Calculate the average force \( F \): The impulse can also be expressed as: \[ F \Delta t = \Delta p \] where \( \Delta t = 0.0006 , \text{s} \).

    From this, we can solve for \( F \): \[ F = \frac{\Delta p}{\Delta t} = \frac{-10.64 , \text{kg⋅m/s}}{0.0006 , \text{s}} \approx -17,733.33 , \text{N} \]

Therefore, the average force the bat exerted on the ball is approximately \(-17,733 , \text{N}\).

Final answer: \(-17,733 , \text{N}\)