   # Space Travel: You've managed to hop a flight on a Space Craft which was able to attain a speed of 86.6% speed of light..

110 views

You've managed to hop a flight on a Space Craft which was able to attain a speed of 86.6% the speed of light. You and your twin brother were both age 20 when you left. When you returned, your twin brother was age 40.

How old are you?

Hint: Lorentz Contraction Equation posted Sep 17, 2016

+1 vote

As an object moves closer and closer to the speed of light the time that it experiences will be longer and longer for an observer in a stationary frame of reference.   answer Sep 17, 2016
Yes, 30 years old. You are correct, complete with a detailed explanation along with the Lorentz Equation.
A useful reference is simply to remember that .866 speed of light = 50% less aging.
I was thinking at first what's up with the velocity being such a specific value.
Yes, and that's what peaks curiosity. One of the reasons why cats are the preferred pet of intellectuals.  They are indifferent but yet so incredibly curious.  Just like scientists.

In order to get the reference point of 50% less aging, I needed to do several trial/error values for velocity squared.  And voila', .866 when squared gives .75 and then 1 - .75 = .25 and sq rt of that = .5 or 50% less aging.

Trial and error are the whole basis of math/science and often lead to serendipitous discoveries..  In fact those "post-its" by 3M company are the epitome of exactly that.

Similar Puzzles
+1 vote

A ball is thrown upwards with speed v from the top of a tower and its reaches the ground with speed 3v.
What is the height of the tower?

A helium balloon leaves the ground at a point A and rises vertically at uniform speed.
At the end of 5 minutes, Rohan finds the angular elevation of the balloon as 30 degree.
If the point at which Rohan is standing is 550 m away from point A, what is the speed of the balloon in m/s?

A tap is opened to fill a bucket, and water flows from the tank through a pipe. Now, as shown in the diagram, consider two points A and B on the vertical part of the pipe which has a uniform cross section. If the pipe is completely filled with water and the water flows steadily, then at which point is the speed of the water flow greater?

+1 vote

A rocket, initially at rest in deep space, starts its thrusters, which then burn and eject fuel at a uniform rate to provide constant thrust to the rocket.

How does the speed of the rocket vary with time?

a) The speed remains constant
b) The speed increases at a constant rate
c) The speed increases at a decreasing rate
d) The speed increases at an increasing rate