A particle is projected from a level ground making an angle θ with the horizontal (x-direction). The vertical (y) component of its velocity changes with its x coordinate according to the graph shown in figure. Calculate θ (in degree). Take g = 10 ms-2.

In projectile motion x-component of the velocity will remain constant and at the highest position of projectile y-component of the velocity should be zero.Hence, from graph, uy=10m/svy becomes zero when x= Range 2∴ Range =20m  ∴2uxuyg=20∴ux=10m/s ∴tan⁡θ=uyux=1 ∴θ=45∘