First, find the acceleration. Use a formula that involves acceleration, initial velocity, final velocity, and time.

• Initial velocity = 64 m/s.
,
• Final velocity = 0 m/s.
,
• Time = 1.6 s.
Use the given magnitudes to find a.

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.