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Forces

Mahi Tuatahi: Draw a diagram indicating all the forces acting upon you


Drawing Force Diagrams



Muscle Contraction & Light-Headedness

Source


Pātai: Vector Reminder

On your whiteboards, add these vectors (head to tail) to find the resultant (net) force acting.


Pātai: Acceleration

For each, calculate the acceleration that a $5kg$ object would experience.


Equilibrium

A state of zero acceleration (constant velocity) due to $F_{net} = 0$.


Recall: Newton’s Second Law

Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration. $F=m \times a$

TLDR: The acceleration created by a force depends directly upon the mass of the object.

Source



Pātai: Terminal Velocity

Source

  1. What is my net force?


  2. What is my acceleration?


  3. Why does it not equal $g$?


  4. What is my drag and weight forces were balanced?



Whakatika

Source

  1. What is my net force?
    $620N$ down
  2. What is my acceleration?
    $F=ma, a=\frac{F}{m}=\frac{620}{72}=8.61ms^{-2}$
  3. Why does it not equal $g$?
    Because friction is acting against the weight force!
  4. What if my drag and weight forces were balanced?
    $F_{net}=0$ and therefore $a=0$ and I would be in equilibrium.

Akoranga 22 Mahi Tuatahi

Quizizz!


Ngā Whāinga Ako

  1. Be able to label different forces
  2. Be able to label forces on an angle

Write the date and ngā whāinga ako in your book


Source




Support/Normal Force

Draw equal and opposite weight and normal forces on your diagram.


Whakatika


Support/Normal Forces on an Angle



Calculating a Missing Force


Task/Ngohe

Worksheet - everything up to but not including the Work section.


Case Study

Step 1. Consider what we know about the motion of the object, and what this implies about the net force acting upon the object.


Question 1


Question 1 Whakatika


Question 2


Question 2 Whakatika


Question 3


Question 3 Continued


Question 3 Whakatika


Question 3 Whakatika Continued


Practise / Whakawai