1. Physics on Friday

2. To do…Friday Answers for first test Questions on Homework handout
Class example problem
Hand in the graph created by you walking before the motion detector with the analysis
Talk about the causes of motion

3. To do Monday Hand in Handout #3 Hand in Graph work
Divide up, calculate velocity, calculate acceleration, determine overall velocity
Forces- general information
Forces –laws of motion
Forces- free body diagram
Homework #4
Test thursday

4. Any questions on the homework handout?
Results are due on Monday,
if needed

5. New homework 3 more question on Handout #4
Grade old homework and pass back tomorrow
Test on Friday (primarily constant acceleration problems and review)

6. Do Now problem Joe runs with a constant velocity of
5.4 m/s for 20 s before he reaches a pile of leaves. It takes 1.5 s for Joe to come to a stop in the pile. What is his rate of acceleration in the leaf pile and how far did Joe travel overall?

7. Answer
Vf = Vi + at
0 = a(1.5)
= -3.6 m/s2

8. What causes objects to move or change their motion?

9. Forces Contact (applied) Forces Non-contact Forces
Electromagnetic forces (most common)
Non-contact Forces
Gravitational (most common)
Fields
Anything that pushes or pulls is a force
Units in Newtons (for this class)

10. Weight is a Force Force due to the pull of gravity
Weight (W) = mass X acceleration due to gravity
On earth, everything in free-fall accelerates at the same rate (9.8 m/s2) towards Earth

11. Demonstration that all objects are pulled at the same rate
Paper and book
Paper-vs-paper
The only reason why things do not fall at sam rate is air resistance

12. Determine your weight in Newtons
Take you weight in lbs and divide by 2.2
The 1st action converts from lbs  kg
Kg is the common unit for Mass
Mass is the amount of stuff that makes up an object

13. Mass is the measure of the inertia of an object
Inertia = the amount resistance to change in motion
The object that is the most massive, changes its velocity the least when a constant force is applied
Golf, Magic Tricks

14. Difference between mass and weight
Mass = measure of the amount of matter that makes up an object
Weight is the amount of Force generated due to the pull of gravity

15. To find your weight in Newtons
Weight = mass x 9.8
9.8 = acceleration due to gravity on earth
Change the location (moon, into space, on Jupiter): Change the acceleration value
Moon 1/6th of earth = 1.67
Jupiter about 2.5 times Earth = 25

16. What weighs 1000 N?

17. Football player (220 lbs)

18. What weighs 100 N?

19. Freshman backpacks

20. What weighs 10 N?

21. The average textbook

22. What weighs 1 N?

23. A smallish apple