I believe the answer is C
Hope this helps :)
Your answer is C. Dark Matter.
Answer:
a.After
second Mr Comer's speed

b.Distance travelled by Mr.Comer in
seconds

Explanation:
a. Lets recall our first equation of motion 
Now we know that
,
and

Plugging the values we have.




Then Mr.Comer's speed after
sec

b.
Lets find the distance and recall our third equation of motion.

So
distance covered.
Dividing both sides with 2a we have.

Plugging the values.


So Mr.Comer will travel a distance of
.
Answer:
42.96 km/s
Explanation:
From the conservation of Energy

Mass gets cancelled

= Escape velocity of Earth = 11.2 km/s
= Velocity of projectile = 44.4 km/s

The velocity of the spacecraft when it is more than halfway to the star is 42.96 km/s
Answer:
t = 0.437 s
Explanation:
The speed of sound is a constant that is worth v = 343 m / s
v = d / t
t = d / v
the time it takes for the sound to reach Clark at d = 150 m is
t = 150/343
t = 0.437 s
This same sound takes much longer to reach you
t₂ = 127 10³/343
t₂ = 370 s