Motion, Newton's Laws
Resources: Glenbrook High School Physics; United States Air Force; CSU Stanislaus; University of Utah; Boston University Dept of Physics; Online Journey Through the Universe website; NASA
a. Discuss and apply Newton's
laws (i.e.,first, second, third, and law of universal gravitation)
motion, acceleration, projectile motion, free fall, problem solving, Newton's
laws of motion including momentum.
b. Define pressure and relate it to fluid flow and buoyancy (e.g., heart valves, atmospheric pressure)
c. Describe relationships among position, distance, displacement, speed, velocity, acceleration, and time, and perform simple calculations using these variables for both linear and circular motion- CLICK ON "a." ABOVE
d. Identify the separate forces that act on a body (e.g., gravity, pressure, tension/compression, normal force, friction) and describe the net force on the body
e. Construct and analyze simple vector and graphical representation of motion and forces (e.g. distance, speed and time)- CLICK ON "a." ABOVE
f. Identify fundamental forces, including gravity, nuclear forces, and electromagnetic forces (magnetic and electric), and explain their roles in nature, such as the role of gravity in maintaining the structure of the universe
g. Describe the causal relationships among heat, friction, and motion
h. Explain and calculate mechanical advantages for levers, pulleys, and inclined planes
Prior to Newton's laws students need to understand motion: Describing motion in words-(Be sure to study carefully each animation)
Look for the concepts of :Instantaneous SpeedAverage VelocityConstant Velocity
Describing Motion Using Drawings and Diagrams- (Be sure to study carefully each animation)
Describing Motion Using Graphs
Position vs. Time Graphs
Velocity vs. Time Graphs
Free Fall and the Acceleration of Gravity- (Be sure to study carefully each animation)
Projectile Motion- (Be sure to study carefully each animation)
Characteristics of the Projectile's Pathway- Describing Projectiles with Numbers-Horizontal and Vertical VelocityDescribing Projectiles with Numbers- Horizontal and Vertical Displacement
Identify the separate forces that act on a body (e.g., gravity, pressure, tension/compression, normal force, friction) and describe the net force on the body -in addition to the material above, from this point to the subject "Define Pressure and relate it to fluid flow and buoyancy" below, subjects deal with elements 9.1 a. c and e. .
An object will remain at rest or in uniform motion in a straight line unless acted upon by an external unbalanced force (LAW OF INERTIA)
Balanced and Unbalanced Forces- Introduction
F= ma (Force = mass times acceleration)
An unbalanced force acting on an object produces an acceleration OR an acceleration is evidence of an unbalanced force.
Mass and Weight- Review
Combining both Newton's First and Second Law we have the most powerful knowledge to keep safe as we drive on today's highways or... if we choose to ignore the concepts... accident, injury and possibly even death.
After you click on the link below, set the speed of the cars to 80 miles per hour.
Measure how long your own car at home is in feet and set the distance between cars to that number. Look for "d=" and type in the number and change the m (meters) to ft (feet). in the graphic below d is set to 12.0 m (meters). Type in the length of your car where the 12.0 is and click on the down arrow and change m to ft.
When you press the reset button (see picture to the left) (1), cars travel from left to right with the yellow car in the lead. You have already changed the speed of your cars to 80 ) and changed m/s to mi/h by using the down arrow. You have already entered the length of your car and changed m to ft . This length becomes the distance between each car... this is your starting place.
The coefficient of friction between your tires and the road (leave as is). However, consider how stopping distances may change on wet highways, ice, snow... etc.
You will watch the lead car (yellow) until it turns RED. and then IMMEDIATELY CLICK ANYWHERE IN THE AREA OF THE PICTURE TO THE LEFT WHERE THE RED LETTERS ARE.
If ALL the cars have stopped without crashing, then you are traveling just the right distance from the car in front of you. A CRASH OCCURS WHEN ONE OR MORE OF THE CARS SHOW AS A RED-LINED BOX, FILLED ONLY BY THE COLOR OF THE BACKGROUND.
IF ANY of the cars crash, you are following too close. IF THIS IS THE CASE, YOU PROCEED IN TWO STEPS. 1) First, decrease the speed by 10 mi/h increments, keeping the distance the same. Report the lowest speed where you had no accidents.
2) Secondly, keeping the speed at 80 mi/h, increase your distance between cars. For example, in the case to the left your car was 12 feet long. Next try 24 feet separation... next 36 feet... etc. until you have NO accidents at all. Obviously, if your car is 8 feet long, you start at 8 feet and increase by increments of 8. Report the distance where there are no accidents at 80 mi/h
How many OF YOUR CAR LENGTHS will you have to have between you and the car ahead of you need to be there to keep safe on the highway. How will your own driving habits change?
Click here to find out how we can stay safe while we drive
Introduction- also includes concepts of center of gravity (not required)
A train traveling at 10 meters per second has a much greater momentum (force of motion) than does a housefly traveling at the same velocity. (Momentum is a vector as well as force, acceleration and velocity.)
Linear Momentum (p = mv)
Law of Conservation of Linear Motion- When two objects in linear motion collide, the "post-collision" momentum of the two objects is the same as the "pre-collision" momentum of both objects. In otherwords, the total linear momentum of an isolated system is the same if there is no external unbalanced force acting on the system.
Angular Momentum- Angular momentum arises when an object goes around a path around a fixed point. L= mvr
Law of Conservation of Angular Momentum- In the case of a planet in its elliptical orbit does is at a different distance from the fixed point. It's velocity may change slightly also. Therefore at any two points in its orbit, mv1r1 = mv2r2 .
Fluid flow and heart valves:
Identify fundamental forces, including gravity, nuclear forces, and electromagnetic forces (magnetic and electric), and explain their roles in nature, such as the role of gravity in maintaining the structure of the universe
Introduction- the fundamental forces of nature-Introduction to the theories of Unification....
Nuclear forces (strong interaction) holds the atoms together. Without this there would be
- no matter of any type... air, rocks...etc on earth
- no planets, suns or gravity
- no universe
It is very strong but its effects are short-ranged
Electromagnetic forces are weaker than the strong force but are very long ranged. It influences (attraction or repulsion) of other charged particles. Without electromagnetic forces
- electromagnet waves (energy waves) such as UV, visible light, Infrared, gamma, X-rays, etc. would not exist
- there would be no visible light in the universe, cutting off photosynthesis
- lack of photosynthesis eliminates all energy to all living systems and all would die
- no plants would grow
- infrared rays, warming the earth with its energy would not be available and the earth would freeze very quickly
- there would be no oxygen in the atmosphere, Nitrogen, etc.
- all biogeochemical cycles (including the water cycle) would end
- there would be no electricity or magnetic fields g... thus no motors or conveniences for earth's populationFor additional information click here
The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and, as its name indicates, it is very weak. Without radioactivity
- much of our knowledge about the biochemical cycles of the body could not have been clarified. Experiments to learn about the cycles of the body were done through incorporation of radioactive carbon or hydrogen atoms into molecules and following where the radioactive carbon or hydrogen went
- medical diagnostic and treatment procedures using radiation (x-rays, etc.) would not be available
- carbon dating procedures would not have been possible
The gravitational force is weak, but very long ranged. Furthermore, it is always attractive, and acts between any two pieces of matter in the Universe since mass is its source. Gravitational forces
- hold the solar systems and galaxies in their positions
- create the orbits the moons around their planets
- create the orbit of the planets around their suns
- create the orbits of the solar systems around their galactic centers
- the orbits of the other objects frequenting our solar systems and
- govern the journey of galaxies around the "center" of the universe. Without gravitational forces
- the planets and suns would be moving in a straight line away from our sun and we all would have frozen long ago because of the excessive distance from the sun
- all objects of the known universe could not have been formed in the first place
- we would have been thrown off the earth long ago and be floating through space
We can define friction as the resistance to the movement of one body in relation to another body with which it is in contact. For example if we try to slide a wooden block across a table then friction acts in the opposite direction to the movement of the brick. The amount of friction will depend upon the nature of the two surfaces in contact with each other. The energy of movement is conserved. Where friction exists, part of the energy of movement is transferred to heat produced on the objects that move over another. That is why your tires become warm when traveling at 80 miles per hour on a cold winter's day.
If both the block and the table are highly polished (smooth) then there will be less friction than if the surfaces were rough and also the amount of heat produced would be less. If we were to reduce all friction between the tires of car and the road (like on ice), the tires would stay cool, but we would get mad as we drove off the road, unable to turn when the road turned. Many accidents would be caused as a result.If we try to slide one object over another the irregularities in the surfaces of the two objects (their degree of roughness) causes resistance to the movement and we have friction. The energy lost forms heat. If we were rolling one object over another the friction (and heat) still arises because of imperfections in the surfaces. Friction then is a measure of the force pressing the two objects together.
How friction of the movement of the continental plates on earth produces heat- example: the heat melts the rocks and volcanoes are formed.
Details of other physics concepts