Question

iss 3rd Q m velocity k saath kyu nhi solve ke sake !?
acceleration. se kyu ??
why to take relative acceleration & solve why not relative velocity ?​

Answer 1

Answer:

according to your question, here acceleration is constant , but we cannot say about velocity that's how to change velocity. but velocity will change in projectile motion.

Answer 2

$\huge\underline\mathfrak\purple{Answer}$

$Since \: the \: ball \: is \: returning \: back \: to \: the \: floor \\ \:Displacement \: in \: y \: direction \: will \: be \: \\ s_y \: = 0$

$g_{eff} \: = g \: - ( - 2) = 10 + 2 \\ = 12m {s}^{ - 2}$

$velocity \: in \: vertical \: direction \: \\ u_{y} \: = \: 4 \sin(30) \\ = 2m {s}^{ - 1}$

$s_{y} \: = u_{y}t \: - \frac{1}{2} g_{eff} {t}^{2} \\ \\ 0 = 2t \: - \frac{1}{2 } \times 12 \times {t}^{2} \\ \\ 2t \: = \: 6 {t}^{2} \\ \\ t \: = \frac{1}{3} sec$

Thank you! ❤