Weight (AP)
AP Physics
Gravity Near the Earth's Surface
The acceleration due to gravity, g, is not perfectly constant — it varies slightly by location.
NY
9.803 m/s2
Denver
9.796 m/s2
North Pole
9.832 m/s2
G = Gravitational constant = 6.67 × 10-11 Nm2/kg2
Practice
Mars has a mass 1/10 that of Earth and a diameter 1/2 that of Earth. The acceleration of a falling body near the surface of Mars is most nearly…
g = GmEr2
Substitute changes into equation
Answer: 4 m/s2
Giancoli p. 131) 32, 30
Earth Data
Mass
5.974 × 1024 kg
Mean Radius
6,371 km
Orbital Velocity
Ex) Prove that the orbital velocity of a satellite does not depend on the mass.
mv2/r = GmmEr2
v = (GmE/r)-1
From the equation we see that orbital V and Period T is only determined by orbital radius.
Enrichment
Einstein's Conception of Gravity
The Elegant Universe - PBS
Mythbusters Moon Landing Hoax 4 HQ