Physical Science

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Physical Science

• Chapter 3
• Section 1

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• Net force acting on an object causes object to
  accelerate in the direction of net force
• Force motion are connected
• An object will have greater acceleration if a
  greater force is applied to it.
• The mass of an object and the force applied to it
  affect acceleration.

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Newtons 2nd Law of Motion

• Newtons 2nd law of motion connects force, mass,
  and acceleration in the equation acceleration
  equals net force divided by mass
• Uses the equation
• F ma

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• Friction
• Force that opposes motion between two surfaces
  that are touching each other
• Microwelds
• Area where surface bump stick together
• Static Friction
• Friction between two surfaces that are not moving
  past each other
• Sliding friction
• Force that opposes the motion of two surfaces
  sliding past each other
• Rolling friction
• Friction between a rolling object and the surface
  it rolls on

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• Air resistance
• Force that opposes the force of gravity
• The amount of air resistance depends on an
  objects shape, size, and speed.
• Terminal velocity
• Forces on a falling object are balanced and the
  object falls with constant speed
• When a falling object no longer accelerates
• When a falling object has its acceleration due
  to gravity equals to its air resistance

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Chapter 3

• Section 2

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• Law of gravitation
• Any two masses exert an attractive force on each
  other
• Four Basic Forces include
• Electromagnetic force
• Strong nuclear force
• Weak nuclear force
• Gravity
• Gravity
• A long-range force that gives the universe its
  structure
• Acceleration due to Gravity
• 9.8 m/s2

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• Weight
• gravitational force exerted on an object
• decreases as an object moves away from Earth
• W mg
• Objects in space shuttle float because they have
  no force supporting them.

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• Projectiles
• Anything that is thrown
• Have horizontal and vertical velocities due to
  gravity
• Follow a curved path
• Centripetal Acceleration
• Acceleration toward the center of a curved path
• Is caused by a centripetal force, an unbalanced
  force

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Chapter 3

• Section 3

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Newtons 3rd Law of Motion

• For every action there is an equal but opposite
  reaction
• Action-reaction forces act on different objects
  and differ from balanced forces.
• States that forces come in pairs
• Rocket propulsion is based on Newtons third law
  of motion.

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• Momentum
• related to how much force is needed to change an
  objects motion
• equals mass times velocity
• P m v
• Law of conservation of momentum
• Momentum can neither be created nor destroyed, it
  just changes forms
• Momentum of a system before a collision is the
  same as the momentum of a system after the
  collision

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