Can either normal or dark matter stop the universal expansion?
What will be an ideal response?
No, normal matter adds up to only about 1-3% of that to reach the critical density. Dark matter is perhaps 10 times more abundant, but it still adds up to only 20-30% of the mass needed for closure.
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The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about
A) 1 s. B) 2 s. C) 10 s. D) not enough information
Potential: If it takes 50 J of energy to move 10 C of charge from point A to point B, what is the magnitude of the potential difference between points A and B?
A. 500 V B. 50 V C. 5.0 V D. 0.50 V
A 0.500-kg ball traveling horizontally on a frictionless surface approaches a very massive stone at 20.0 m/s perpendicular to wall and rebounds with 70.0% of its initial kinetic energy
What is the magnitude of the change in momentum of the stone? A) 18.4 kg ? m/s B) 14.0 kg ? m/s C) 3.00 kg ? m/s D) 1.63 kg ? m/s E) 0.000 kg ? m/s
Many of the extrasolar planets that have been detected directly to date are
A) very large and at great distances from their parent star B) small and at great distances from their parent star C) small and close to their parent star D) very large and close to their parent star