|
This month's Challenge Question:
Spaceships
launched from earth often use gravitational assist or "slingshot" to
accelerate. Shouldn't the spaceship end up with the same speed it started with
since any acceleration gained on approach to the planet would be lost as the
spaceship moves away? How does this work?
And the answer is:
If the planet were stationary,
it's true the spacecraft wouldn't gain any additional speed, though it could
change direction, which technically is an acceleration (change in speed or
direction). However, planets are actually orbiting the sun at very high speeds.
For instance, Jupiter moves about the sun at roughly 8 mi/s. The spacecraft
that approaches a planet from behind its direction of motion can steal some of
that planet's angular momentum, thus increasing its own.
The spacecraft doesn't gain any
speed as compared to the planet; however, it has picked up a lot of speed as
compared to the sun. To put this in perspective, Pioneer accelerated to a speed
of 82,000 mph when it passed Jupiter in 1973.
| 
Re: Accelerating Spaceship: Newsletter Challenge (07/01/11)
Good Answers:
"Almost" Good Answers: