WELCOME!! Welcome. Please come in and sit in your seat. Then wait for further instructions. Bellwork will start when the bell rings. Today is Wednesday, April 8th.

CATALYST 5 MINUTES Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation List the three types of friction.

CATALYST 4 MINUTES Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation List the three types of friction.

CATALYST 3 MINUTES Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation List the three types of friction.

CATALYST 2 MINUTES Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation List the three types of friction.

CATALYST 1 MINUTE Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation List the three types of friction.

TIME’S UP!!!!!

Please remember to remove ear buds when I am addressing the class or lecturing.

Catalyst Answers Using your textbook pages 65, 71, and 72: Copy the Second Law of Motion Equation F=ma List the three types of friction. Static, Sliding, and Rolling

AGENDA Catalyst Notes

ANNOUNCEMENTS Retakes over Motion assessment must be done by April 17th. Think of who you can work with on Friday.

Today we will see how forces cause the motion of objects to change. TODAY’S OBJECTIVE Today we will see how forces cause the motion of objects to change. HS-PS2-1: Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.

Force, Mass, and Acceleration When you throw a ball hard, you exert a much greater force on it. It has a greater change in velocity over a shorter period of time. Acceleration is the change in velocity over time. A ball thrown hard has greater acceleration than a gentle soft ball thrown. When you throw a softball and baseball as hard as you can, they don’t have the same speed. This is due to their masses. The acceleration of an object depends on its mass as well as the force exerted on it.

Newton’s Second Law Where acceleration is in m/s², Force is in Newtons (N), and mass is in kg.

Newton’s Second Law A tennis player hits a ball. Its acceleration is 5000 m/s² and its mass is 0.06 kg. The net force is what? You push a wagon that has a mass of 8 kg. If the net force on the wagon is 4 N, what is the wagon’s acceleration.

Friction Why does the skateboard stop moving? Friction-the force that slows down the skateboard and brings it to a stop. The amount of friction depends upon the type of surface and the force pressing the surfaces together. https://www.youtube.com/watch?v=-gFzqX83dmM Friction is due to microwelds between two surfaces. The larger the force pushing the two surfaces together is, the stronger the microwelds will be. https://www.youtube.com/watch?v=VUfqjSeeZng

Friction Static: Frictional force that prevents two forces from sliding past each other. Sliding: The force that opposes the motion of two surfaces sliding past each other. Rolling: Frictional force between a rolling object and the surface it rolls on.

Friction What would happen if you dropped an ant from Sears (Willis actually :/) tower? It could end up in Lake Michigan. What if you jumped from the top of the tower? SPLAT This is due to air resistance, which opposes the motion of objects that move through the air. The lighter you are, the more it affects you.