DO NOW Write your HW in your agenda Update your table of contents:

Have pages 152 and 153 ready to be checked

Fold the notes and attach to page 155.

You have 10 minutes to find and identify the types of friction on the 15 cards hidden in the room. (all can be seen without moving anything)

Page #

Title Date

154 (We will be using this page later in the week)

155 Newton’s Laws of Motion 04/13

NET FORCESThe combination of all the forces acting on an object is the net force

COMBINING FORCESIf the forces are

in the same direction, the net force is the sum of those forces.

If the forces are in opposite

directions, the net force is the

subtraction of those forces.

BALANCED FORCES AND UNBALANCED FORCES

If the combined forces result in a net force of 0, this is called a balanced force.

If the combined forces result in a net force that is NOT 0, this is called an unbalanced force.

THIS IS NEWTON’S FIRST LAW OF MOTION

An object at rest will remain at rest and an object moving at a constant velocity will continue at the same velocity, unless acted upon by an unbalanced force.

INERTIAWhether an object is moving or not, it resists any change to its motion.

This tendency to resist a change in motion is called inertia.

INERTIA

Inertia depends on mass, which means some objects have more inertia than others.

The greater the mass of an object, the greater its inertia, and the greater force is required to change its motion.

Using Newton’s first law of motion, explain why the skater moved.

DO NOW

Update notebooks and record HW.

Pay attention for a challenge I am issuing you.

Pages Title Date

156 Motion Misconceptions 04/14

157 Newton’s 3rd Law 04/14

Which requires more force to move- a heavier object or a lighter object?

NEWTON’S SECOND LAW OF MOTION

States that…

The acceleration of an object depends on the object’s mass and on the net force acting on the object.

NEWTON’S SECOND LAW OF MOTION

This relationship between force, mass, and acceleration can also be written as an equation.

• F=ma

NEWTON’S SECOND LAW OF MOTION

UNITS!

A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s2. Calculate the net force that causes this acceleration.

Force= 55kg * 2.0m/s2

Force=110N

PRACTICE PROBLEM

EXIT SLIP

You are sitting in a moving car and the driver suddenly pushes down on the brake.

1. Describe your motion if you were wearing a seatbelt.

2. Describe your motion if you weren’t wearing a seatbelt.

3. Which law of motion does this situation relate to?