a) 0.321 ly
b) 0.321 light years is not far in astronomical terms. Alien life would need to transmit at tremendous power in order for their radio transmissions to be detectable. Their radio signal also needs to be stronger than background noise in order to be distinguishable. Therefore it is unlikely that radio transmissions from alien life will ever be detected.
Answer:

Explanation:
m = Mass of roller coaster = 2000 kg
r = Radius of loop = 24 m
v = Velocity of roller coaster = 18 m/s
g = Acceleration due to gravity = 
Normal force at the point will be

The force exerted on the track is
.
The acceleration that Andrew experience during his ride is 3.6m/s²
The formula for calculating centripetal acceleration is expressed as:
a = v²/r
v is the speed
r is the radius
Given the following expression
v = 6m/s
r = 10m
Substitute the given parameters into the formula
a = 6²/10
a = 36/10
a = 3.6m/s²
Hence the acceleration that Andrew experience during his ride is 3.6m/s²
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