stops,
- stops,
- kinetic energy zero, all converted to potential energy
- falls back down
- potential energy converted back to kinetic energy
- hits hand with same velocity it was launched with
- Velocity decreases,
- kinetic energy of ball being converted to gravitational potential energy
- energy has been conserved
- If velocity high enough, ball will escape from Earth
- Law of Conservation of Energy shows the escape velocity is the square root of 2 times the circular velocity
- vescape = sqroot(2)*vcircular, or
- vescape = sqroot(2GM/r)
- for Earth escape velocity = sqroot(2)*7.8 km/s = 11.2 km/s
- need twice as much energy to escape than to just orbit