1 / 15

Newton’s Second Law of Motion Force & Acceleration

Newton’s Second Law of Motion Force & Acceleration. Introduction to Science A. King EHS. Acceleration. Galileo define rate of change of velocity as acceleration. The term acceleration is typically used when the velocity increases.

ksena
Download Presentation

Newton’s Second Law of Motion Force & Acceleration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Newton’s Second Law of MotionForce & Acceleration Introduction to Science A. King EHS

  2. Acceleration • Galileo define rate of change of velocity as acceleration. • The term acceleration is typically used when the velocity increases. • The term deceleration is typically used when the velocity decreases – another way of saying this is that “deceleration” is when negative acceleration is occurring. • In both cases, “acceleration” is the process that’s actually occurring.

  3. ΔV Acceleration = --------- t Where ΔV is the change in velocity and t is the time it takes for the velocity to change. ΔV : : x t acc Calculating Acceleration

  4. Speed and velocity are easily measured in distance/time units, such as miles/hr, m/s, etc. Units of acceleration are more complicated, and have to take other stuff into account. Sample problem: What is the acceleration if we speed up from 10 km/h to 30 km/h in 10 seconds? Acceleration = Δv/t (30 km/h – 10 km/h)/ 10 sec = 2 km/h/s Units for Acceleration

  5. Acceleration depends on the net force. Acceleration ~ net force.

  6. Mass • Mass is a measure of an object’s inertia and a measure of how much material an object contains. (It depends on the number and kind of atoms making the object up.) • Mass is measured in grams: grams, kilograms, milligrams…

  7. Weight • Weight depends on gravity. • Weight is the force due to gravity that acts on an object’s mass. • Although weight and mass are different from each other, they are directly proportional to each other. • 1 kilogram weighs 9.8 newtons.

  8. Volume • Volume is a measure of space.

  9. Newton’s Second Law states: • The acceleration produced by a net force on an object • is directly to the net force. • Is in the same direction as the net force. • Is inversely proportional to the mass of the object. • In formula: F = m x a

  10. By using consistent units, such as newtons (N) for force, kilograms (kg) for mass, and meters per second squared (m/s2) for acceleration, we get the exact equation: Δ v vf – vi Acceleration = -------- = ---------- t t

  11. Acceleration Problems • While drag racing out of our school parking lot, I time myself at a speed of 40 meters per second seven seconds after starting. What was my acceleration during this time? • A = vf – vi / t • = (40 m/s – 0 m/s )/7s • = (40 m/s)/7s • = 5.7 m/s/s

  12. Friction • Occurs when one object rubs against something else. • Occurs for solids, liquids and gases. • Always acts in a direction opposite to motion. • The amount of friction between two surfaces depends on the kinds of material and how much they are pressed together.

  13. Free Fall • When an object is dropped in a place with gravity (k.e. not deepspace), gravity causes the object to fall downward. • When this occurs, the object is said to be in “free fall.” • For problems like this, we’ll imagine that gravity is the only force that’s acting on the object – wind resistance and other stuff will be ignored.

  14. Let’s consider the following data table: The increase in speed per second is the acceleration which in this case is 10 m/s/s. The instantaneous speed of an object that is accelerating is equal to the acceleration multiplied by the amount of time the object is falling. In equation form: v = at How fast is an object moving in free fall?

  15. F v : : : : t a m a x x Formulas Δv acceleration vf - vi acceleration : : : : x x t t acc acc Newton's 2nd Law freefall distance weight instantaneous speed d Wt : : : : g m x x t2 ½ g

More Related