Unit 5 motion and forces

• Mass: the amount of matter in an object

  *Mass is measured in grams or kilograms*
• Weight: is the force of gravity acting on an object
• Your mass will never change
• Your weight can change based on the amount of gravity
• Force is a push or pull
• Energy changes from PE to KE when force is applied
• one force is gravity, which pulls all objects towards the center of the earth.
• All changes in motion require the input of a force
• Measured in Newtons (N)
• Motion: is a change in position overtime
• Refrence point: is a stationary (not moving object)
• Distance is the change of position
• Speed= distance/time
• Distance= speed x Time
• Time= distance/speed
• Speed is the rate of movement pr how fast something moves.

  *Anything that moves after a set amount of time has speed
• Velocity: the rate of movement or how fast something moves PLUS the direction
• Direction= speed X time
• Speed= Direction/time
• Time= Direction/speed
• Distance: how far an object travels *Does not depend on direction*
• Displacement: difference between an objects final position and its starting position *Does depend on direction*
• Average speed= total distance/ total time
• straight line=constant speed
• Acceleration the rate at which velocity changes over time
• an object accelerates if its speed, direction, or both change
• Average acceleration= final velocity-starting velocity/ time taken to reach final velocity
• As velocity increases so does acceleration
• As velocity decreases so does acceleration
• when there is constant velocity there is no accleration
• ` Net force is the sum of all the forces that act upon an object
• Air resistance: frictional force that acts on objects as they travel through the air
• all objects attract towards each other
• if the mass increases the force of gravity increases
• if the distance increases the force of gravity decreases
• Newtons first law: if an object is at rest it stays at rest or if an object is in motion it stays in motion at the same speed and in the same direction unless acted upon by an unbalanced force, law of inertia.
• Newtons 2nd law is the acceleration of an object increases with increased force, decreases with increased mass, and in the same direction as the force
• When one object exerts a force on another object, the second object exerts an equal and opposite force on the first object