final notes

friction-

net force-

Inertia:

1. how could you use a roller skate, a sidewalk and water to demonstrate how rolling friction works? the water would slow you down because it slows your rolling friction.
2. A marble lying in the middle of the floor, use Newton's laws to describe what would happen to the marble? The marble will not move until a force acts upon it. The gravity is pulling down on the marble and the floor is pushing up on the marble.
3. a broom strikes the marble while you are sweeping. Use Newton's laws to describe what will happen to the marble? this relates to the 1st law because a force acts upon it to make the marble move.
4. Use newton's 3rd law to describe what interactions there is between the marble and the broom. if you push the marble with a certain force the marble is going to push back with a force also. This means for every action there is a reaction.
5. What force must be applied to a 10kg object to make it accelerate to 6m/s2? 60Newtons
6. Why is terminal velocity an example of balanced force. you cant go any faster because of air resistance. The falling force is as hard as the air resistance.
7. When you step out of a boat on to a dock, the boat moves. Why? For every action there is a reaction. The boat is pushing so are you.
8. Describe circular motion. Which of Newton's laws helps you describe circular motion? the 2nd law because the object will accelerate in the direction of the force
9. if action and reaction force pairs are equal and opposite how can anything move? give an example. rocket. row boat. they act of different things.

chapter 19 notes Newtons 3rd law

• Newtons 3rd law states that a force always in equal and opposite pairs and for every action there is an equal and opposite reaction.

• Action-Reaction forces-are always the same but they push or pull in opposite directions

• Gravitational force- is also known as weight
• The second law explains how to calculate the acceleration of an object if its mass and the forces acting on it are both known.
• In circular motion, the centripetal force is always perpendicular to the motion.
• Terminal Velocity is reached when the force of gravity is balanced by air resistance.
• An object can speed up, slow down, turn in direction of the net force, if unbalanced forces act upon.

Newton's 2nd law of motion Notes 5/11/10

Newton's 2nd law of Motion-

~Connects force, mass, and acceleration

~Explains that an object acted upon by a force will accelerate in the direction of the force.

~Force=mass*acceleration

Gravity-

~an attractive force between two forces

~depends on the mass and distance between 2 objects

pg. 550-555 ? 1-6

1. The turn creates friction between the wheels and the ground when the wheels are rolling and turning.
2. Static friction is between the atoms on two surface that are in contact.
3. Friction adds resistance between two touching surfaces therefor it made discovering newton's first law of motion complicated.
4. No its not moving because the net force is zero.
5. A) unbalanced B) balanced C) unbalanced
6. Static friction is caused by atoms on the two surfaces are in contact this causes them to stick or weld together. Sliding friction slows down an object that slides. Rolling friction occurs between the ground and part of the tire touching the ground. this keeps the tire from slipping on the ground.

• BONUS QUESTION--How does a space shuttle taking off relate to Newton's 1st law? It starts with zero for speed and gains speed going in a straight line therefore relating to Newton's 1st law.

Newton first law Notes

Force-push or a pull

1. The combination of all forces acting upon each other is net force.
2. Balance Forces two forces acting upon each other that balance each other out.
3. Unbalance force when one force is larger than the other.

Newton's 1st law- an object will remain at rest or moving with a constant speed unless a force is applied.

Friction- is a force that resists sliding between two touching surfaces through air or water.

1. Friction slows objects down.

• 3 Types of Friction:

1. Static friction- friction that prevents an object from moving
2. Sliding friction- friction due to roughness between two objects
3. Rolling Friction- Friction between the ground and the wheel.

Motion Test note!

1. Speed- how fast something is going(m/s-distance divided by time)

• Average speed-how fast you covered a certain distance
• Velocity- speed and direction.(m/s + direction going)
• Acceleration-the process of speeding up(m/s2)
• Negative acceleration-the process of slowing down(-m/s2)
• Mass-How much matter is in an object(g, kg)
• Inertia-the resistance to stop an object
• Momentum-mass times velocity of an object the measure of an objects resistance to stopping(p=kg*m/s)
• Displacement-the actual distance you cover from one point to another
• Distance-the actual distance of point
• Law of Conservation of Momentum-the total momentum of objects that collide together is the same before and after they collide

Questions-examples-

1. The distance ways-constant, different directions, deceleration and acceleration.
2. A car travels 10km north, 5 km east, 15km south, then 5km north. What is the distance traveled.-35km. What is the displacement.-k=5km east
3. An Object's velocity chanves from 30 m/s-23m/s in 3 seconds. What is the acceleration? (23m/s-30m/s/3s= -2 1/2 m/s2)
4. A 5kg object moving at 20m/s collides with an object that is 10kg moving at 5m/s. They stick together and move off. What is they're final velocity? (5kg*20m/s+10kg*5m/s=>100kg*m/s+50kg*m/s divide by total weight=>10m/s