Measurements

Image
1.general physics  1.1 length and time  -i-Physical Quantity Physical Quantities A physical quantity is a property of an object that can be measured with a measuring instrument. A physical quantity is usually expressed as “a magnitude ( numerical value)  and a  physical unit or more ” Example :- Normal body temperature of a healthy human being is  37  0 C -ii-Length Measuring Length. Length is “the distance between two points in a space”. According to SI units, the length quantity is expressed in meter. There are several kinds of measuring devices used to measure quantity of length, among others, are as follows. Tools used… a-   Measuring tape. b-   Ruler c-   Vernier callipers. d-    Micrometer Measurement of length Length is measured accurately through many meth...
Post a Comment

Momentum

momentum and impulse 

A moving object has momentum. This is the tendency of the object to keep moving in the same direction. It is difficult to change the direction of movement of an object with a lot of momentum.
You can calculate momentum using this equation:
Momentum (kg m/s) = mass (kg) × velocity (m/s)
Impulse 
The units of impulse and momentum are equivalent [N s = kg m/s]. 
Ft = mv – mu

                           

Impulse

Newton's second law (Fnet = m • a) stated that the acceleration of an object is directly proportional to the net force acting upon the object and inversely proportional to the mass of the object. When combined with the definition of acceleration (a = change in velocity / time), the following equalities result.

F = m • a

or

F = m • ∆v / t
 

If both sides of the above equation are multiplied by the quantity t, a new equation results.

F • t = m • ∆v

This equation represents one of two primary principles to be used in the analysis of collisions during this unit. To truly understand the equation, it is important to understand its meaning in words. In words, it could be said that the force times the time equals the mass times the change in velocity. In physics, the quantity Force • time is known as impulse. And since the quantity m•v is the momentum, the quantity m•Δv must be the change in momentum. The equation really says that the
Impulse = Change in momentum  

Principal of conservation of momentum 
For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.









Comments

Post a Comment

Popular posts from this blog

Conditions of equilibrium

Image
Equilibrium  Centre of mass Scalers and vectors A scalar is a quantity that only has a magnitude (so it can only be positive) for example speed. A vector quantity has a direction as well as a magnitude, for example velocity, which can be negative. • More ways to add vectors (Pythagoras’s theorem and the parallelogram rule) : 
Read more

Mass weight and density

Image
MASS AND WEIGHT AND DENSITY Weight  = force of gravity = mass x free fall acceleration = ma = mg Force = Weight = mg   the acceleration of free fall for a body near to the Earth is constant Notes:- 10 m/s 2  = 10 N/kg   Weight is the force which causes an object to accelerate downwards and has the value mg. The value of the acceleration caused by weight can be calculated from Newton’s second law, using the equation F = ma Weight unit is N (because it is a force) It is measured by spring balance   Mass     Weight Define It is the amount that body contains“It is not a force” It is the force of gravity acting on the body“It is a force” Units kg N  (kg.m/s 2 ) Scalar or vector Scalar quantity(No direction) Vector quantity(always vertical downwards) Device used to measure Pan  balance.Beam balance. Spring balance Dependence on place Mass of a body remains the same throughout the universe (doesn’t change from one...
Read more

Motion

Image
Speed Speed can be defined as the distance covered by a moving object in unit time taken. Speed is a  scalar quantity  and hence it can only be represented by magnitude not by direction.In other words, “ The speed of an object can also be considered as the magnitude of the velocity of the object ”.  Speed Formula : Speed =  D i s t a n c e   c o v e r e d T i m e   t a k e n   X =  d t   where,  X  = speed of the moving object;  d  = distance traveled by the moving object;  t  = time taken to travel distance ‘d’.  Formulas for finding area, gradient and acceleration are mentioned in image below. acceleration and deceleration are related to changing speed 
Read more