What are the limitations to travelling between stars?
What will be an ideal response?
The distances between stars are almost beyond comprehension. The fastest human device ever launched, the New Horizons probe, will take about 90,000 years to travel the distance to the nearest star. The obvious way to overcome these huge distances is with tremendously fast spaceships, but even the closest stars are many light-years away.Nothing can exceed the speed of light, and accelerating a spaceship close to the speed of light takes huge amounts of energy. Even if you travel more slowly, your rocket would require massive amounts of fuel. If you were piloting a spaceship with the mass of 100 tons (the size of a yacht) to the nearest star, 4 light years away, and you wanted to travel at half the speed of light so as to arrive in 8 years, the trip would require 400 times as much energy as the entire United States consumes in a year. These limitations not only make it difficult for humans to leave the Solar System, but they would also make it difficult for aliens to visit Earth. Reputable scientists have studied unidentified flying objects (UFOs) and have never found any evidence that Earth is being visited or has ever been visited by aliens. Humans are unlikely ever to meet aliens face to face. However, communication by radio across interstellar distances takes relatively little energy.
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Describe the separation of the superforce and the effect it had on the Universe
What will be an ideal response?
As a result of friction between internal parts of an isolated system
a. the total mechanical energy of the system increases. b. the total mechanical energy of the system decreases. c. the total mechanical energy of the system remains the same. d. the potential energy of the system increases but the kinetic energy remains the same. e. the kinetic energy of the system increases but the potential energy of the system remains the same.
Components: When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 5.1 m/s. What was the vertical component of Jeff's velocity?
A. 4.8 m/s B. 4.3 m/s C. 3.8 m/s D. 3.4 m/s
When a liquid boils and changes to a gas, it is said to have undergone a change of ________
Fill in the blank(s) with correct word