Motion and ForcesMotion and Forces

What makes us move and why we What makes us move and why we move in that particular way…move in that particular way…

What Is Motion?What Is Motion?

• MotionMotion: when an object changes when an object changes position over time when compared position over time when compared with a reference pointwith a reference point

Reference Reference PointPoint

Object Object In In

MotionMotion

How Can We Describe How Can We Describe Motion?Motion?

• 3 Ways To Categorize Motion3 Ways To Categorize Motion

1. Position1. Position

2. Direction of Motion 2. Direction of Motion

3. Speed3. Speed

Which way did he go, which way did he go???

Follow The Directions!!!!Follow The Directions!!!!

The direction of the The direction of the objects motion is objects motion is dependentdependent on the on the reference pointreference point

If the reference point If the reference point changeschanges, the direction , the direction of the object can also of the object can also be looked at differentlybe looked at differently

What Makes An Object What Makes An Object Move?Move?

• ForceForce: a push or pull on an object: a push or pull on an object

Characteristics of ForcesCharacteristics of Forces

1. Have size

2. Direction

40 Newtons40 Newtons

3. Units = Newtons

Forces Control The Motion of Forces Control The Motion of an Objectan Object• If an object is in moving or even if it is sitting

still, there are still forces acting upon it

If the forces acting on the If the forces acting on the object are balanced, or object are balanced, or equal to one another but equal to one another but in opposite directions…in opposite directions…then the object doesn’t then the object doesn’t move.move.

If one of the forces is If one of the forces is larger, it will move the larger, it will move the object in the direction of object in the direction of that force that force

All Forces Control The All Forces Control The Motion of the ObjectMotion of the Object

• We can use something called a Force We can use something called a Force DiagramDiagram

Net ForceNet Force

• Easy CalculationEasy Calculation

2 Scenarios2 Scenarios

1. If the forces are moving in the samesame direction, addadd them together

2. If the forces are moving in the oppositeopposite direction, subtractsubtract them, leaving the object to move

in the direction of the greater force

ExampleExample

Newton’s LawsNewton’s Laws

1.1. An object in motion tends to stay inAn object in motion tends to stay in motion unless acted upon by anmotion unless acted upon by an outside forceoutside force

2. Force = mass x acceleration2. Force = mass x acceleration

3. For every action, there is an equal 3. For every action, there is an equal and opposite reactionand opposite reaction

One Force Calculation One Force Calculation ExampleExample

5 m/s5 m/s22

ForceForce = = massmass x x accelerationacceleration

ForceForce = = 500 kg500 kg x x 5 m/s5 m/s22

ForceForce = = 2500 N to the West2500 N to the West