Newton's first law of motion:
"Newton's first law of motion states that everybody remains in the state of rest or in uniform motion until and unless it is compelled change its state by an external force."
Factors of Newton's first law of motion:
Newton's first law of motion depends on two factors,
➡1. There should be an external force which is required to move/ accelerate a body.
➡2. A body cannot change its State of rest or of uniform motion on its own until a force is applied which leads to a concept called as Inertia.
Inertia:
"A tendency of a body to remain in its state of rest or of uniform motion i.e a body will be always in rest if it is at rest position and a body will be always in motion if it is at motion."
➡Inertia body depends on the mass of the body.
➡Inertia ∝ Mass of the body
➡Greater the mass higher the inertia, lesser the mass lower the inertia.
➡There are three types of inertia.
1. Inertia of rest
2. Inertia of motion
3. Inertia of direction
➡1. Inertia of rest:
Inertia of rest is defined as the resistance of a body to change its state of rest.
➡2. Inertia of motion:
Inertia of motion is defined as the tendency of a body to continue its motion in the direction of force.
➡3. Inertia of direction:
Inertia of direction is defined as the direction of a body with respect to the direction of the applied force.
"An object moving with some velocity into the air at an angle 90 degrees with horizontal plane is known as Projectile."
➡Velocity an object has two components, one is horizontal component and other one is vertical component.
➡The path of an object which moves in the air in the form of a parabola is called as Trajectory.
➡A projectile has two dimensional motion, one is horizontal dimensional motion and other one is vertical dimensional motion.
➡Uniform velocity along the horizontal direction.
➡Uniform acceleration calendar vertical direction.
➡Acceleration is zero along horizontal direction.
Parameters Of Projectile:
There are 5 parameters of projectile.
1. Maximum height
2. Time of ascent
3. Time of flight
4. Horizontal range
5. Maximum range
➡1. Maximum height( Hmax):
The height at which the vertical component of the velocity becomes zero of a projectile is called as maximum height.
➡2. Time of ascent (ta):
Time taken by the projectile to reach the maximum height is known as time of ascent.
➡3. Time of flight(T):
Sum of the time of Ascent and time of Descent of a projector is known as time of flight.
➡4. Horizontal range(R):
From point of projection, the horizontal distance covered by the projectile is known as horizontal range.
➡5. Maximum range(Rm):
If the Angle of projection is 45 degrees, then the horizontal range will become maximum, this is known as maximum range.
There are two defects in voltaic cell.
1. Local action
2. Polarization
1. Local action:
➡Zinc plate contains carbon and iron particles as impurities.
➡These impurities react with acid present in the voltaic cell and along with zinc particles to form tiny cells creating a local electric circuits known as local action.
➡Usually zinc plate are coated with Mercury to prevent this local action.
➡This Mercury prevent the impurities to come in direct contact with acid to form the local action.
2. Polarization:
➡As the current passes through this cell, the zinc plate start dissolving in the acid to form hydrogen bubbles.
➡This hydrogen Bubbles move towards the copper plate and resist flow of current. This is known as polarization.
➡Depolarisers are used to reduce this polarization.
➡Oxidizing agents act as depolarizer which reacts with hydrogen Bubbles and this converts into water.
➡Usually potassium dichromate, manganese dioxide, copper sulphate are used as depolarizers.
Length:
"The distance between two fixed points is known as Length."
➡SI unit of length is metre
Measurements
➡Light year:
➡Distance travelled by light in one year is known as light year.
➡One light year is equal to 9.46
x 1015 m.
➡Astronomical unit( A.U):
➡The distance between the Earth and the Sun is known as astronomical unit.
➡One astronomical unit is equal to 1.496 x 10 ^ 11 metre
➡Parallactic second( parsec):
➡Parallactic Second is the biggest unit of distance.
➡It is equal to 3.26 times of the light year.
➡1 parsec is equals to 3.08 x 10 ^ 16 m
➡Femtometer( Fermi):
➡Femtometer is the smallest unit of distance.
➡1 Fermi is equals to 10 ^ - 15 m
➡Least count:
➡Least count is the smallest quantity that can be measured accurately.
➡Least count is equal to 1 mm( on regular scale).
➡Curved object:
➡Length of a curved object is measured using a thread, then this thread is spread along the side of a regular measuring scale.
