i need help in statics and dynmics asap

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Practicality of Statics and Dynamics

Space: the Physics Frontier

Andrew Frantzen

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Space!

  • The exploration of space is all physics, all the time
  • Space is a vacuum, which means that in certain ways the physics are simpler out there than here on earth
  • Friction, especially air-related friction aka drag is a large part of earth-based physics, but velocity lost to drag is negligible in space

The “rules” of space

  • Everything is always moving, nothing is truly stationary
  • The moons of planets rotate as they orbit around their planets, and those planets rotate as they orbit the sun
  • Also, while we generally think of the sun as stationary, the sun itself rotates and it orbits the center of the Milky Way galaxy
  • This is what makes knowing how to calculate frames of reference so important
  • rB = rA + rB/A
  • vB = vA + vB/A

  • Remember: there is no single fixed reference in space

Physics!

  • The movement of objects in space follow the laws of physics, and as such their movements can be predicted
  • In fact, they have to be predicted, because this knowledge is essential to allow us to successfully explore any objects beyond our atmosphere
  • Probes, rovers, landers, and even humans all went beyond the earth with physics

Cool, huh?

  • Those pink and green objects are asteroids, the green ones being the “Jupiter Trojans”
  • They're not just randomly found around Jupiter, they there because they’re in Jupiter's stable “Lagrangian points”
  • Jupiter’s gravity does many things, it even helped us to explore Pluto
  • How?

New Horizons

  • Notice how New Horizons sped way up after passing Jupiter?
  • That’s because New Horizons received a gravity assist from Jupiter, which increased the velocity of the craft 4 km/s
  • 4 km/s is 14,000 km/h or 9,000 mph
  • This shortened its voyage to Pluto by three years, from 2018 to July 2015 thanks to Jupiter’s massive gravity

And it got cool pictures of Io erupting

(Simplified) Physics!

  • Jupiter’s motion is a key. A gravity assist with Jupiter involves not a stationary planet (see left), but a planet with enormous angular momentum as it revolves around the Sun. In the diagram at right, Jupiter's motion along its solar orbit has been illustrated with a vector colored red. The spacecraft acquires this Sun-relative vector, or a significant portion of it, during its interaction with Jupiter.

  • You can see how the red vector is added to VIN and VOUT. The resulting vector shows how the spacecraft's velocity, relative to the Sun, takes on a nice boost from Jupiter. Notice how rotation of the vector from VIN to VOUT (the bending of the spacecraft's path by the planet's gravity) helps increase the result. This trajectory bending is the other key.

  • Vectors for Pluto!

Have a simple physics problem as an analogy:

  • The kid sees his tennis ball moving away from him at 30 miles per hour. So does the Sun, sitting on the stationary platform.
  • The engineer driving the train sees the ball coming at about 80 MPH, since the train is moving 50 MPH with respect to the ground.
  • Remember, there is no single fixed reference in space.
  • The train and ball interact at 80 MPH. The ball rebounds from the front of the train at nearly the same velocity of 80 MPH,
  • This 80 MPH can be added to the 50 MPH speed of the train, because the ball acquired it from the train.
  • The result approaches a total of 130 MPH.

It’s not rocket science!

Oh wait, it totally is.

Fin