1. it is difficult to search for it . Because infrared rays will never penetrate through earth atmosphere.
2. we are unaware of how it looks like and we only know it is red and will glow . A damaged star also looks like this.
3. Dust also makes is hard to detect Dyson spheres . So we will get confused between Dyson sphere and a star surrounded by dust.
Answer:
2. How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/gºC? c=0.90J/g. 9 (2 sigs.)
Explanation:
The answer is B because if you use process of elimination, you find that A is invalid because Venus is the second planet. C is out because Mars is the 4th planet. D is out because we are nowhere near the Andromeda Galaxy. We are millions of light years away.
Answer: The center of gravity is 1.1338 m away from the left side of the barbell
Explanation:
Length of the barbell = 1.90 m
The distance center of gravity from left = x
Mass on the left side = 25 kg
The distance center of gravity from right = 1.90 - x
Mass on the right side = 37 kg
At the balance point: 
The center of gravity is 1.1338 m away from the left side of the barbell
2) transverse
hope this helped:)
