Today’s Puzzler:

1. Today’s Puzzler: • Explain why an inflated balloon (made of a rigid plastic material) will rise to a definite height once it starts to rise, while a submarine will always sink to the bottom of the ocean once it starts to sink. • If you know the answer, select 1 on your clicker. • If you give up, select 2.

2. ANNOUNCEMENTS • Physics tutoring 7 – 9 pm Tue and Thu in Olin 131. Tutors are Laura Brill and Brock Taute.

3. 1 of 3 Car A is moving with constant positive velocity. Car B is moving with constant positive acceleration. Both cross x = 0 at the same time. Which graph best represents their motion? 1 2 x vx B A A B t t 3 4 x vx A A B B t t 3

4. 2 of 3 x • An object has the position (x) vs. time (t) graph shown. Its x acceleration is: • positive. • zero. • negative. t 4

5. 3 of 3 x • An object has the position (x) vs. time (t) graph shown. Its x acceleration is: • positive. • zero. • negative. t 5

6. ANNOUNCEMENTS • Physics tutoring 7 – 9 pm Tue and Thu in Olin 131. Tutors are Laura Brill and Brock Taute. 6

11. 1 of 3 Car A is moving with constant positive velocity. Car B is moving with constant positive acceleration. Both cross x = 0 at the same time. Which graph best represents their motion? 1 2 x vx B A A B t t 3 4 x vx A A B B t t 11

12. 2 of 3 x • An object has the position (x) vs. time (t) graph shown. Its x acceleration is: • positive. • zero. • negative. t 12

13. 3 of 3 x • An object has the position (x) vs. time (t) graph shown. Its x acceleration is: • positive. • zero. • negative. t 13

14. PROJECTION SCREEN 1 4 1 4 1 4 1 4 2 5 2 5 2 5 2 5 3 6 3 6 3 6 3 6 HAND IN TODAY’S ACTIVITY SHEETS 14