Question

A projectile has the same range r 40 m for two angles of projection. if t₁ and t₂ are the times of flights find t₁t₂ given g=10m/s²

Answer 1

Range is same
R1=R2
Range is same for complementary angle. Complementary angle means their sum should be 90°
U1^2sin2¢/g=U2^2sin2(90-¢)/g
(sin2¢=2sin¢cos¢)
U1=U2=U
t1=2U1sin¢/g
t2=2U2sin(90-¢)/g
t1 t2=2U^2sin2¢/g^2