projectiles formulas

BASIC TERMS use in projectiles formulas

 When a particle is projected into the air,

  • then the particle is called a projectile.

  • the point from which the particle is projected is called the point of projection.

  • the angle that the direction in which it is projected makes with the horizontal plane through the point of projection is called the angle of projection;

  • the  path which the particle describes is called its trajectory;

  • the distance between the point of projection and the point where the path meets any plane drawn through the point of projection is its range on the plane;

  • the time that elapses before it again meets the horizontal plane through the point of projection is called the time of flight.

  • the initial velocity with which the projectile is projected is called the velocity of projection.

  • the maximum height reached by a projectile during its motion is called greatest height.

Check out Physics Formulas and NCERT Solutions for class 12 Physics prepared by Physics Wallah. 

LIST OF PROJECTILES FORMULA

  • Velocity and direction of motion after time ‘t’  v2 = u2 – 2ugt sinα + g2t2 and tanθ = projectiles formulas

  • Velocity and direction  of motion at height ‘h’ v2 = u2 – 2gh and tan θ = projectiles formulas

  • Greatest height  attained by a projectile h = projectiles formulas

  • Time for the greatest height =

  • Time  of flight  t = projectiles formulas

  • Range = projectiles formulas

  • Maximum Range = projectiles formulas

Here u : initial velocity of the body

α : Angle of projection

θ : Angle which the velocity of the projectile at a certain point makes with the horizontal (It is the tangent to the path of the projectile at the point)

g : acceleration due to gravity

Note:   

  • The path of a projectile is a parabola, given by y = x tan α - projectiles formulas

i.e. projectiles formulas

with vertex ≡ projectiles formulas

latus rectum    = projectiles formulas

and height of directrix = projectiles formulas

  • The velocity at any point is equal in magnitude, to that which would be acquired by a particle in falling freely from the directrix to that point.

  • There are two direction for a given range and velocity and also two times for a given height.

Range and Time of Flight on an Inclined Plane: 

If from a point on a plane which is inclined at an angle β to the horizon, a particle is projected with a velocity u, at an angle α with the horizontal, in a plane passing through the normal to the inclined plane and the line of greatest slope, then

  • Time of flight, T= projectiles formulas

  • Range = projectiles formulas

  • Maximum range up the plane = projectiles formulas

   

  • Range, time of flight and maximum range down the plane is obtained by putting –β for β.

  • For a given range and given velocity there are two different directions of projection which are equally inclined to the direction of projection for maximum range.

Example :If the maximum range of a particle is R, show that the greatest height attained is . A body can throw a ball 60 meters. How long is the ball in the air, and what height does it attain.

Detail Explanation :    Let the particle be projected with a velocity v at an angle α  with the horizontal. 

Horizontal range = projectiles formulas

Greatest height = projectiles formulas

The range is maximum where sin2α = 1 ⇒ α = 45° 

⇒ R = projectiles formulas  ⇒ H =

Now R = 60 metres  ⇒ h = 15 metres 

Now  time t of  flight = projectiles formulas =

  • t2 = projectiles formulas ⇒   t = 3.5 sec aprox. 

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