• Just like a bird faces air resistance when it flies, satellites in orbit face drag from the remnants of the Earth's atmosphere.
• This resistance can play a big role in a satellite's life! 🛰️

• Air resistance affects the motion of objects, making them slow down or change direction.
• For projectiles: Air resistance...
  • Reduces their range.
  • Changes their trajectory to a steeper angle.

🎈Fun Fact: Throwing a frisbee? It'll get slowed down by air resistance! But if you could throw it in space, it would keep going...and going...

• The atmosphere gets thinner as you go higher.
• Satellites in low orbit still experience some atmosphere, causing a "drag" on them.
• Result? Collisions between satellite and gas atoms
  • Transfer energy from the satellite to the atmosphere.
  • The atmosphere heats up, satellite's energy decreases.
  • Satellite's orbital radius decreases... But, paradoxically, its speed must increase!

🚀 Real-World Example: It's like when ice skaters pull their arms in. They spin faster (increase in speed) because their rotational radius decreases.

• For a satellite's energy

          E = W + E_K​ Here, E is total energy, W is gravitational                      potential energy, and EK​ is kinetic energy.

• Interesting observation: The gravitational potential energy is negative but has twice the magnitude of the kinetic energy.

🔍 Deep Dive: Why is gravitational potential energy negative? Think about lifting an object from the ground. The object gains energy, so the Earth must lose an equal amount, making it negative.