Physics

posted by .

Suppose you wish to visit a star which is 450 light years away, and that you want your 21000 kg rocket to move so fast that you only age 20 years during the round trip.

a. How fast must the rocket travel relative to the Earth? Give your answer as the fraction of the speed of light.

b.Assuming your turn-around time is near zero when you reach the star, how long does your trip take according to your friends and family back on Earth?

c.How much energy is needed to accelerate the rocket to this speed?

d.The entire earth uses approximately 5*1020 Joules of energy each year. What is the ratio of you answer to part c to the total Earth's energy usage in one year?

  • Physics -

    L/V=20 years
    L=20V

    using L= Lo/1-v2/c2 lenght contraction
    20V=430/1-v
    V = 0.996 c

    is it right..please give right answer plz..

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics "Space Travel"

    Suppose you want to go to the immense red giant Betelgeuse, which is about 500 light years away. (A light year is the distance that light travels in one year.) You plan to travel at constant speed in a 1000 ig rocket ship. A: If the …
  2. English

    1. During the next few years, you will grow fast. 2. In the next few years, you will grow fast. 3. The next few years, you will grow fast. 4. Next few years, you will grow fast. (Are they all the same?
  3. 8th grade math

    Light travels approximately 5.87 X 10^12 miles in one year. This distance is called a light year. Suppose a star is 2 X 10^4 light years away. How many miles away is that star?
  4. 8th grade math

    Light travels approximately 5.87 X 10^12 miles in one year. This distance is called a light year. Suppose a star is 2 X 10^4 light years away. How many miles away is that star?
  5. College Physics

    Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel?
  6. colleg physics

    Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel?
  7. college physics

    Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel?
  8. physics

    Marks: 2 The time taken by the space craft moving at a speed equal to half the velocity of light to go from star A to star B is 2 years as calculated at the Earth station. Which of the following is correct for the time measured by …
  9. Physics

    In an attempt to reduce the extraordinarily long travel times for voyaging to distant stars, some people have suggested traveling at close to the speed of light. Suppose you wish to visit a star which is 410 ly away, and that you want …
  10. physics

    Even though we have found an earth sized planet around the nearest star Alpha Centauri B, we're not even close to getting there. To see this let's think about the duration of a flight to Alpha Centauri B, which is about 4×1016 meters …

More Similar Questions