Answer
3.43 s
Work Step by Step
Let down be the negative direction.
First time interval:
$x= ut + \frac{1}{2}at^{2}$
$(-9.50)= (0)t + \frac{1}{2}(-9.8)t^{2}$
$t=\sqrt \frac{9.50}{4.9}\approx 1.3924$ s
Second time interval:
$x=vt-\frac{1}{2}at^{2}$
$(5.70)=(0)t-\frac{1}{2}(-9.8)t^{2}$
$t=\sqrt \frac{5.70}{4.9}\approx 1.0785$ s
Third time interval:
$x= ut+ \frac{1}{2}at^{2}$
$(-5.70+1.20)= (0)t + \frac{1}{2}(-9.8)t^{2}$
$t=\sqrt \frac{4.50}{4.9}\approx 0.9583$ s
Total time = 1.3924+1.0785+0.9583$\; \approx$ 3.43 s
