In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A particle is projected from a point O O\,O on horizontal ground with speed 21 m s−1^{-1}−1 at an angle θ \theta\,θ above the horizontal. Air resistance is modelled as negligible.
The particle passes through the point which is 20 m horizontally and 5 m vertically from OOO.
By writing down expressions for the horizontal and vertical displacements of the particle in terms of t t\,t and eliminating ttt, find the two possible values of θ\thetaθ.