Answer:
[tex]2.4 N\cdot s[/tex].
Explanation:
The equation that models the travel of the object is:
[tex]m \cdot v{o} + \Sigma F \cdot \Delta t = m \cdot v_{f}[/tex]
The impulse is:
[tex]\Sigma F \cdot \Delta t = m \cdot (v_{f} - v_{o})[/tex]
By replacing terms:
[tex]\Sigma F \cdot \Delta t = (0.40 kg) \cdot [- 2 \frac{m}{s} - 4 \frac{m}{s} ]\\\Sigma F \cdot \Delta t = - 2.4 N \cdot s[/tex]
The magnitude of the impulse acting on the object is [tex]2.4 N\cdot s[/tex].
