JEE Main202126 Feb 2021Evening ShiftPhysicsMotion in Two DimensionsActual
The trajectory of a projectile in a vertical plane is y = α x - β x 2 , where α and β are constants and x & y are respectively the horizontal and vertical distances of the projectile from the point of projection. The angle of projection θ and the maximum height attained H are respectively given by
Options
- Atan - 1 α , 4 α 2 β
- Btan - 1 β α , α 2 β
- Ctan - 1 β , α 2 2 β
- Dtan - 1 α , α 2 4 β
Correct answer
D. tan - 1 α , α 2 4 β
Step-by-step solution
y = α x - β x 2 comparing with trajectory equation y = x tan θ - 1 2 g x 2 u 2 cos 2 θ tan θ = α ⇒ θ = tan - 1 α β = 1 2 g u 2 cos 2 θ u 2 = g 2 β cos 2 θ Maximum height : H H = u 2 sin 2 θ 2   g = g 2 β cos 2 θ sin 2 θ 2   g H = tan 2 θ 4 β = α 2 4 β