Mechanics Flashcards
Father of mechanics
Newton
Father of modern physics
Max plankck
Medieval newton
Ancient galileo
Kinematics
Motion of the body
Dynamics
Motion of the body along with reasons
Scalar quantities
Which has only magnitude but no direction
Vector has both mag and direction
Vector quantities
Velocity displcement acceleration force impulse momentum weight torque
Displcement
The shortest path between two points called displcement
Sometimes it will be negative or zero
First law of equation
V= u + at
Equation descibes about velocity and time
2 nd law of equation
S= ut+ 1/2 at2
It describes about time and position
Third law of equation
It describes about the velocity and displcement
Different masses are dropped from certain height which one reach first
All are reach at ssame time
Galileo
We can’t observe because air create disturb
In vaccum all are reach at a same time
Newton first law
Law of inertia
Inertia at rest
Inertia at motion
Inertia at direction
Newton second law
The amount of force applied on object is directly proportional to mass of the object and it’s acceleration
F= ma
Momentum
Masa * velocity
If it has mass and velocity
It has also momentum
Conservative laws of linear momentum
Sum of momentum before collision is equal to sum of after collision
Without collision where we observe
Gun fire
Canon tank
Rocket motion
Bomb explosion
Bullet and wooden block
Impulse
The large force acting on a body within short span of time
Nail with hammer
Axe to cut tree
Ball with bat
Hockey stick
Force * time cgs dyne sec
Impulse also called change in the momentum
Reducing the impulse
Shock absorbers are used in the automobiles
Soft materials are filled in the long jump
Takes his hands back before catching the ball
Egg on bed
Mobile packing
Helmet wearing
Newton third law
Every action there is also opposite reaction
Running. Swimming
Flying bird
Rocket. Missiles and jet flights
Work
W = f * displacement
Product of Force and displacement
Nm - joule
Cgs dyne cm called erg
One joule
10 to the 7 erg
One newton
10 to the power 5
If angle given between force and displacement
W= fscos@
Positive
Negative
Zero
Positive work
Force and displacement are in same direction
Degree lies less than 90
Object kept above the surface of the earth
Koolie kept object
Bulb at some height
Pe =Mgh
Negative
Force and displacement are opposite in direction
Only obaerved in ramps
Zero work
W=fscos@
If f= 0 w = 0
S zero work zero
90 work zero
Railway cookie force and 90 so work is zero
Carrying suitcase is also work zero
Power
The rate of doing work
Pani retunu called work
P = work / time
Si joule) / sec called James watt
Invented steam engine
Cgs unit erg / sec
One hp
746 wats
Energy
The capacity to do work is called energy
Potential energy
Kinetic energy
Si unit joule
Potential
The energy possessed by the body of it’s position or place
Stored energy
Pe = mgh
Strectched rubber
Catball stored energy
An arrow inthe bent bow
Water stored in a reservoir
A stone on the top of a mountain
The ending point of the potential energy is the starting point of ke
Raised hammer
Raised axe
Pounding rod
Calling bell
Compressed cycle bell
Kinetic energy
The energy possessed by a body due to its motion
1/2 mv2
The relationship between kinetic energy and linear momentum
P^2 /2m
If the velocity of the body doublee then ke will be
Four times
If the momentum of the body doublee then kinetic energy also
Four times
If the velocity of the 1/3 then ke will be
1/9
Mechanical energy
Aeroplane
Kiye
Clouds
Rocket motion
Flying bird
Friction
Surface irregularity
Roughness of the surface
Advantages of a friction
Walking running writing
Holding the things
Ignition of match stick
Breaking system
Disadvantages of friction
Energy loss
Wear and tear
Depreciation
Life span decrease
How to overcome the friction
Polishing
Lubricants
Ball bearings
Steam lining
Graphite used as lubricant
Drag
Friction due to fluids
Centripetal
Sun and solar system exam ple of centripetal
Gravitational force act as centrioetal
Electirns revolve nuckess and acts as electrostatic force
Centrifugal
Away from the centre
Mixers
Grinders
Washing machine
Butter seperated from the milk
Seperation blood cells from the good
Seperation of sugar crystals from molasis
Seperation of honey from honey bee wax
