Answer:
a

b

Explanation:
From the question we are told that
The speed of the spaceship is 
Here c is the speed of light with value 
The length is 
The distance of the star for earth is 
The speed is 
Generally the from the length contraction equation we have that
![l = l_o \sqrt{1 -[\frac{v}{c } ]}](https://tex.z-dn.net/?f=l%20%20%3D%20%20l_o%20%20%5Csqrt%7B1%20-%5B%5Cfrac%7Bv%7D%7Bc%20%7D%20%5D%7D)
Now the when at rest the length is 
So



Considering b
Applying above equation
![l =l_o \sqrt{1 - [\frac{v}{c } ]}](https://tex.z-dn.net/?f=l%20%20%3Dl_o%20%5Csqrt%7B1%20-%20%20%5B%5Cfrac%7Bv%7D%7Bc%20%7D%20%5D%7D)
Here 
So



If velocity is decreasing, then acceleration is in the direction
opposite to the velocity.
If the object is moving in the direction that you call 'positive',
then acceleration is negative.
Answer:
The material must be durable (quality of the material requirement)
Explanation:
The design criteria set for the materials used for technological design are;
1) The materials should be affordable (less costly)
2) The materials should be last for a long duration (high durability)
3) The material should be readily available (easily sourced)
Therefore, given that the engineers initially had the criteria for the required plastic to be of high quality and to be readily available, and that the poly-carbonate they found is long lasting and not too costly, the criteria met that was set initially was the quality criteria of durability.
I think it’s C. Stroke if not then D