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Speed, Velocity, Acceleration, & Force. Motion: The change in position of an object Reference Point: a place or object used for comparison to determine if something is in motion. (also called frame of reference)
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Motion: The change in position of an object Reference Point: a place or object used for comparison to determine if something is in motion. (also called frame of reference) An object is in motion if it changes position relative to a reference point.
Speed: The distance an object travels in one unit of time. Average Speed (average velocity): v = d ÷ t (v = velocity, d = distance, t = time) Example: an object rolls 2 meters in 4 seconds. 2 ÷ 4 = 0.5 m/s To solve for missing factor when the other 2 are known: t = d ÷ v or d = v∙t
Velocity: Speed in a given direction (example: 10 km/hr north) • Graph: a picture of the data used to assist in data analysis
Acceleration: The rate at which velocity changes {change in speed and/or direction} • Acceleration: a = vf – vi t (a = acceleration, vf = final velocity, vi = initial velocity, t = time) Ex: an objects initial velocity is 2 m/s but increases to 4 m/s second after 5 seconds 4 m/s – 2m/s = 2 m/s 5 s 5 s 0.4 m/s2 Δ (delta) is a symbol that means change in. To solve for missing factors when the other 2 are known: a = Δv÷t Δv =a∙t t = a∙ Δv
Force: A push or pull exerted on an object • Newton (N): A unit of measure for force. 1 N = the force required to accelerate 1 kg of mass at 1 m/s2 • Balanced Forces: Equal forces acting on an object in opposite directions (no change in motion) • Unbalanced Forces: A nonzero net force, which changes an object’s motion. • Net Force: The overall force on an object when all individual forces acting on an object are added together.
The 4 Fundamental Forces: • Gravity: The force that pulls objects toward each other (more detail in later units) 2. Nuclear Forces • Strong Force: force in the nucleus that causes protons and neutrons to be attracted to each other. • Weak Force (electrical force) is a long range force and causes repulsion of protons far apart. It is responsible for the decay of isotopes (more in later units & chemistry). • Electromagnetic force (more detail in later units) 4. Dark Energy : believed to be the cause of universal expansion (space science)