Posted by **Jordan Stark** on Monday, July 9, 2012 at 4:55pm.

A spaceship and its occupants have a total mass of 170000kg . The occupants would like to travel to a star that is 31 light-years away at a speed of 0.40c. To accelerate, the engine of the spaceship changes mass directly to energy.

How much mass will be converted to energy to accelerate the spaceship to this speed? Assume the acceleration is rapid, so the speed for the entire trip can be taken to be 0.40c, and ignore decrease in total mass for the calculation.

- Physics -
**drwls**, Tuesday, July 10, 2012 at 7:24am
Compute the increase in kinetic energy desired. Divide that by c^2 for the mass loss required.

You will be accurate enough if you use (1/2) M V^2 for the kinetic energy required. For V, assume 0.4c

Delta M = (1/2) M V^2/c^2 = (1/2)M*0.16c^2/c^2

= 0.08 M

You don't need to use the 31 light year distance.

- Physics -
**Jordan Stark**, Wednesday, July 11, 2012 at 12:22pm
I tried that and it didn't work at all

## Answer This Question

## Related Questions

- physics - several students are riding in bumper cars at an amusement park. the ...
- physics - Goku wants to visit Andromaeda galaxy which is 2 million light years ...
- physic - The star nearest to our solar system is said to be 3.8 ly away. How ...
- physics - At what rate must a cylindrical spaceship rotate if occupants are to ...
- physics - At what rate must a cylindrical spaceship rotate if occupants are to ...
- Physics - Suppose you wish to visit a star which is 450 light years away, and ...
- Physics - If there was a way to accelerate a spaceship close to the speed of ...
- Physics - In an attempt to reduce the extraordinarily long travel times for ...
- Physics - In a novel from 1866 the author describes a spaceship that is blasted ...
- Physics - Your dog has been diagnosed with a terminal illness for which there is...

More Related Questions