1. Motion and Forces
Chapter 2

2. Bell Work 1/21/10
Copy each of these statements onto your bell work sheet. Then decide if they are true or false. If false correct them.
Speed includes direction, while velocity does not.
A moving object covers the same distance in less time if its velocity is greater.
Acceleration measures only change in speed.

3. Please begin working on your foldable or PowerPoint
Bell Work 1/22/10
Please begin working on your foldable or PowerPoint
On your bell work sheet write down “working on project” for today

4. Bell Work 1/25/10
Please begin completing the Map Practice Packet. Write your answers for each question on your yellow bell work sheet for today. PLEASE DO NOT WRITE IN THE PACKET

5. Force 2.1 Notes
forces occur when one object pushes or pulls on another object
We say that one object exerts a force on another object to cause it to accelerate.

6. Describing Forces forces are describe according to: strength and
direction

7. Two types of Forces Unbalanced Force
two forces acting in the same direction OR
One stronger force acting in the opposite direction of a weaker force.
*Unbalanced forces cause an object to accelerate!

8. Balanced Force equal forces acting in opposite directions
* balanced forces will NOT change the object’s motion!

9. Newton’s First Law
An object at rest will remain at rest unless acted upon by an unbalanced force!

10. continued
An object moving at constant velocity will continue moving at constant velocity unless acted upon by an unbalanced force.

11. Law of Inertia
Newton’s first law is often referred to as the Law of Inertia.
Inertia is a property that describes an object’s resistance to changes in motion.
if an object is moving, inertia keeps it moving.
if an object is at rest, inertia keeps it at rest.
Mass – is the amount of matter in an object.
Mass is a measure of inertia.
the more mass an object has the more inertia it has. This means it will take more force to get it to accelerate.
the opposite is also true: less mass, less inertia, less force.
mass is measured in kg.

12. How are mass and inertia related?
The more matter in an object, the harder it is to get the object to accelerate or you could say the harder it is to overcome the object’s inertia.

13. Force 2.2 Notes Newton’s Second Law of Motion
Explains a relationship between force, mass and acceleration
Often expressed as: force = mass x acceleration
Simply stated: An object’s acceleration depends on the mass of an object and the strength and direction of the force acting on it.

14. Force = mass x acceleration
Units:
acceleration – m/s/s
mass – kg
force – kg x m/s/s or Newton (N)

15. Rearranging the Force Equation
To calculate mass:
Mass = ___force___
acceleration
To calculate acceleration:
Acceleration = force
mass

16. Using the formula acceleration = force/mass
We know the following:
as force increases, acceleration increases.
as mass increases, acceleration decreases.
to get an object to accelerate, you must increase force or decrease mass.