CHAPTER 2 MOTION

PS 10 a,b The student will investigate and understand scientific principles and technological applications of force, and motion. Key concepts include: a) speed, velocity, and acceleration b) Newton’s laws of motion

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SPEED and VELOCITY  Distance: how far something has moved; SI unit meters (m)  Speed: the distance an object travels per unit time speed = distances = d time t  Speed is measured in meters per second (m/s)  Velocity: the speed of an object and the direction it travels

ACCELERATION  Acceleration: the rate of change of velocity Unit is meters per seconds squared (m/s²)  Three ways to accelerate:

CHAPTER 3 FORCES

 Force: a push or pull that one body exerts on another; a force can change an objects motion SI unit for force is Newtons (N)

INERTIA  the tendency of an object to resist change in its motion  an object at rest will stay at rest, and an object in motion will stay in motion until acted upon by a force  the greater the mass, the greater the inertia

NEWTON’S FIRST LAW OF MOTION  an object moving at a constant velocity keeps moving at the same velocity until a net force acts on it; and if an object is at rest, it stays at rest until a net force acts on it Examples:

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NEWTON’S SECOND LAW OF MOTION  the net force acting on an object causes the object to accelerate in the direction of the net force  FORMULA: force = mass x acceleration F = m x a

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FRICTION  the force that opposes motion between two surfaces that are touching each other; friction will slow down the motion of the object

GRAVITY  Law of Gravitation: any two masses exert an attractive force on each other  the strength of the gravitational force depends on: The mass of the objects The distance between the objects

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WEIGHT  the gravitational force exerted on an object by Earth  measured in Newtons (N)  Weight = mass x 9.8 m/s² W = m x 9.8 m/s²

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NEWTON’S THIRD LAW OF MOTION  for every action force there is an equal and opposite reaction force

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