pls explain this [problem with steps

1. when it is accelerating above with an acceleration of a = 1/7g

the net acceleration acting on the screw due to both gravity and elevator wuld be = a+g

thus now we can calculate the time of decent using the second equation of motion with

s = 2.9 m

a = 1/7g + g = 8/7g

and u = 0

 

2. when it is moving with constant velocity it means it is not accelerating thus

the net acceleration on it would be g

and we can find the time similarly using a = g

in the previous equation.