Applications of Force

1
Applications of Force

• Anyone who has never made a mistake has never
  tried anything new.-Albert Einstein
• Overview
• Vector Components
• Force Lab
• Review of Common Forces (Dynamics)
• Free Body Diagrams
• Incline Planes
• Multi-mass Problems
• Static Equilibrium and Torque
• Atwood Machine Lab
• Momentum and Collisions

2
Vector Components

• Motion is rarely in a straight line. We need to
  analyze forces and motion that follows curved
  lines or motion that changes direction abruptly.
• Motion Equations The Big Four
• Uniform motion (constant velocity)
• V ?d
• ?t (velocity and displacement)
  

3

• Uniformly accelerated motion
• A v1 v2
• ?t
• 1. V vi at
• 2. d (v1 v2 )t The Big Four
• 2
• 3. d vi t ½ at
• 4. vf2 vi2 2ad

4
Vector Addition and Subtraction

• In Physics 11 we solved vector problems
  graphically
• Now we will use trig and right angles in a more
  precise method
• vectors at right angles (SOHCAHTOA)
• rarely vectors are at right angles so we
• will resolve the vectors into their
• components

5
Vector Addition

• Step 1 resolve all vectors into their x and y
  components (be careful to indicate if the
  components are negative or positive what
  quadrant they are in)
• Step 2 calculate the total x and y components by
  addition
• Step 3 draw a summary right angle triangle and
  use the pythagorean theorem to calculate the
  hypotenuse (resultant) and angle (direction)

6
Vector Components and Dynamics

• Newtons 1st and 2nd laws of motion are
• An object at rest or in uniform motion will
  remain at rest or in uniform motion unless acted
  upon by an external force
• F(net) ma
• net force is the vector sum of all the forces
  acting on a body

7
Equilibrium - Stationary

• When the net forces add to zero the body is said
  to be at equilibrium.
• The force that will counter the net force to make
  the body stationary is called an equilibriant.
• Problem calculate the equilibriant for the
  forces
• F1 425 N E 63 N
• F2 385 N W 15 N