One second after projection, a projectile is travelling in a direction inclined at 45^ to horizontal. After two more seconds it is travelling horizontally. Then the magnitude of velocity of the projectile is ( g =10 ~ms ⁻² )

Step-by-step solution

When projectile travels horizontally, then t= T 2 T 2 =3 u ~g =3 u , u =30 After time, t =1 ~s , 45^ = v _ y v _ x v _ y = v _ x aligned & u -g t=u & 30-10 1=u aligned aligned & u_x=u =20 & u= u_x^2+u_y^2 = (30)^2+(20)^2 =10 13 ~m / s aligned