1. SECTION 5.8
Satellites and “Weightlessness”

2. SATELLITES AND APPARENT WEIGHT
 How do I find the velocity of satellites?
 How do I find apparent weight?

4. SATELLITES
 Speed is critical
 Must be high enough
so the satellite does
not return to Earth
 Can’t be too high or
else the satellite would
leave Earth’s orbit

5. SATELLITES
 Speed keeps the
satellite in orbit
 The satellite is
constantly falling, but
the Earth curves under
it

6. SPEED OF SATELLITES


7. WEIGHTLESSNESS
 Objects in orbit are said to be weightless
 There is a gravitational force
 A satellite and everything in it are in free fall so
there is no normal force
 This feels like weightlessness

8. WEIGHTLESSNESS
 Besides space, can be
achieved in an airplane
 Steep angle up, followed
by steep angle down
 At the top, 20 – 30
seconds of
weightlessness
 Experience can be your
starting at $4,950

9. APOLLO 13
 “Vomit-Comet”

10. ELEVATOR

11. APPARENT WEIGHT
 If you stand on a scale in
an elevator
 If the elevator is going at
constant speed, there is
no acceleration
 Then the scale would
read the same as your
real weight
 Without a scale, the force
holding her up the is the
normal force

12. APPARENT WEIGHT


13. APPARENT WEIGHT
 Mass = 75.0 kg
 Starting from rest
 Accelerates at 2.00
m/s2 for 2.00 s
 What is her apparent
weight?

14. HOMEWORK
 Page 132
 # 43 - 50