Question

An object is projected with a velocity of 20 m/s making an angle of 45⁰ with horizontal. The equation for the trajectroy is h = Ax – Bx² where h is height, x is horizontal distance. A and B are constants. The ratio A : B is : (g = 10 ms^–2)

• A. 1 : 5
• B. 5 : 1
• C. 1 : 40
• D. 40 : 1

Answer 1

Answer: (D)

40 : 1

Answer 2

u = 20, q = 45º Given h = Ax – Bx² comparing with

y = xtan q – $\frac { \mathrm { gx } ^ { 2 } } { 2 \mathrm { u } ^ { 2 } \cos ^ { 2 } \theta }$ , A = tanq = tan 45⁰ = 1

And B = $\frac { b } { 2 u ^ { 2 } \cos ^ { 2 } \theta } = \frac { 10 } { 2 \cdot ( 20 ) ^ { 2 } \cdot \frac { 1 } { 2 } } = \frac { 1 } { 40 }$

\ $\frac { A } { B } = \frac { 40 } { 1 }$