Answer:
• let's first get time
[tex]{ \rm{s = ut + \frac{1}{2}g {t}^{2} }} \\ \\ { \rm{78.4 = 30t + 5 {t}^{2} }} \\ \\ { \rm{ {t}^{2} + 6t - 15.68 = 0}} \\ \\ { \rm{time \approx \: 2 \: seconds}}[/tex]
• let's find horizontal displacement
[tex]{ \rm{s = ut + \frac{1}{2}g {t}^{2} }} \\ \\ { \rm{s = (30 \times 2) \times ( \frac{1}{2} \times 0 \times {2}^{2}) }} \\ \\ { \rm{displacement = 60 \: meters}}[/tex]
- g is acceleration due to gravity [ vertically: g is 10 m/s². horizontally: g is 0 ]
