First, find the acceleration. Use a formula that involves acceleration, initial velocity, final velocity, and time.
![v_f=v_0+at](https://img.qammunity.org/2023/formulas/physics/college/qgre38q8sgm0h17jd2cw9z9w3fnmh5ftbi.png)
• Initial velocity = 64 m/s.
,
• Final velocity = 0 m/s.
,
• Time = 1.6 s.
Use the given magnitudes to find a.
![\begin{gathered} 0=64\cdot(m)/(s)+a\cdot1.6s \\ a=(-64\cdot(m)/(s))/(1.6s) \\ a=-40\cdot(m)/(s^2) \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/tor9uphicts1ax49lbs20sury96cxj0yk3.png)
Then, use Newton's Second Law to find the force of impact.
![\begin{gathered} F=m\cdot a=0.4\operatorname{kg}\cdot(-40\cdot(m)/(s^2)) \\ F=-16N \end{gathered}]()
Therefore, the magnitude of the force of impact is 16 Newtons.