Given:
The formula to be used is: [tex] \bold{t = \Large \frac{2v_{i} \sin \theta}{g}}[/tex]
Solution:
[tex]t = \displaystyle \frac{2v_{i} \sin \theta}{g}[/tex]
[tex]t = \displaystyle \frac{2(18 \: m/s) \sin 31^{\circ}}{9.8 m/s^{2}}[/tex]
[tex]t = \displaystyle \tt 1.32 \: s[/tex]
Answer: [tex] \large \sf \bold{ \blue{1.32 \: s}}[/tex]
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