Gravity
weight vs mass, F = G mm/d2, inverse square law (tidal effects), G= 6.67 x 10 -11 Nm2/kg2, don’t feel gravity (weight) really feel the supporting force – ‘weightlessness’ is often a lack of supporting force rather than the lack of gravity (rotating space station)
Projectiles: constant
horizontal velocity once thrown,
accelerating vertically, combined into a parabola, falling in
acceleration – 5
m in first sec, velocity = 8km/sec, projectile is constantly falling,
but
Earth’s curvature curves away equally fast, circular orbit – constant
PE and KE,
escape speed 11.2 km/sec
Explain why weightlessness is not truly the absence of weight or gravity. What role does the support force play in weightlessness?
How does distance between two objects affect the force of gravity? Why is distance more important than mass?
How do objects get into orbit around another object (Earth or Sun)? How fast do they have to go to get into orbit? Why? What happens if they go faster? What if they go more slowly?