Question

An object is projected with a velocity 20m/s making an angle 45 with horizontal.the equation for the trajectory is h=ax-bx^2 where h is height,

Answer 1

H = ax - bx²

We compare with :

H = xTan Ф - gx² / 2u²Cos² Ф

a = Tan Ф

b = g/2u²Cos² Ф

a/b = (Tan Ф) / (g/2u²Cos² Ф)

= 2u²Sin Ф Cos Ф / g

g = 10

Doing the substitution we have :

(2 × 20² × Sin 45° × Cos 45°) / 10

= 400 / 10 = 40 / 1

The ratio of a : b

= 40 : 1