Inertia and Newton's third Law

Question 1

Define Inertia

Answer 1

Until acted upon by a resultant force, objects at rest remain at rest and objects moving at a steady speed will stay moving at that speed ( Newtons 1st law)
This tendency to continue in the same state of motion -> Inertia

Question 2

What does an objects inertia mass measure?
How to you get the inertia mass??

Answer 2

how difficult is it to change the velocity of an object

It can be found using Newtons second law, F=MA, rearrange into M = F/A Inertia mass is the ratio of force over acceleration

Question 3

What is newtons third law? 1-3

Answer 3

When two object interact, they exert equal but opposite forces on each other

2) Push somethings, it pushed back against you just as hard
Stop pushing, it stops

3) If forces are always equal, How does anything ever go anywhere?
- 2 forces are acting on different objects

Question 4

Example: Skater A pushes on Skater B (action force)

Answer 4

1) she feels an equal but opposite force from skater Bs hand ( normal contact force )

2) Both skaters feel the same sized force, in opposite directions, so accelerate away from each other

3) Skater A will accelerate further than Skater B as she has smaller mass A = F/M

Question 5

Man pushing against a wall

Answer 5

1) Man pushed wall, normal contact force pushing back on him

2) These 2 force are the same size

3) As the man pushed on the wall , the wall pushes back on him with equal force ( Equilibrium situation )

Question 6

A book resting on the ground

Answer 6

1) Weight of book is equal to the normal contact force

2) But this is not Newton’s third law because the two forces are different types, and both acting on the book