False the North Star never changes it position
Part a)
in horizontal direction there is no gravity or no other acceleration
so in horizontal direction the speed of clam will remain same

Part b)
In vertical direction we can use kinematics



part c)
if the speed of crow will be increased then the horizontal speed of the clam will also increase but there is no change in the vertical speed
Answer:
Total length of spring 0.647 m
Explanation:
We have given mass of the person m = 150 kg
Acceleration due to gravity 
Spring constant k = 10000 N/m
Nominal length of spring = 0.50
According to hook's law


x = 0.147 m
So total length of spring = 0.50+0.147 = 0.647 m