Posted by **Darren** on Thursday, May 5, 2011 at 3:07pm.

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?

## Answer This Question

## Related Questions

- Physics - In an attempt to reduce the extraordinarily long travel times for ...
- college physics - Sirius is about 9.0 light-years from Earth. To reach the star ...
- colleg physics - Sirius is about 9.0 light-years from Earth. To reach the star ...
- College Physics - Sirius is about 9.0 light-years from Earth. To reach the star ...
- Physics "Space Travel" - Suppose you want to go to the immense red giant ...
- 8th grade math - Light travels approximately 5.87 X 10^12 miles in one year. ...
- 8th grade math - Light travels approximately 5.87 X 10^12 miles in one year. ...
- Probability and statistics - Astronomers treat the number of stars in a given ...
- physics - Even though we have found an earth sized planet around the nearest ...
- science - Suppose that you can just barely see a certain star that is at a ...

More Related Questions