Question

The pressure $\left(P\right)$ of wind on a sail varies jointly as the area $\left(A\right)$ of the sail and the square of the velocity $\left(V\right)$ of the wind. The pressure on a square centimetre is 1 gm when the velocity is 16 km/hr. The velocity of the wind when the pressure on a square centimetre is 36 gm is:

• A. $10\frac{2}{3}$ km/hr
• B. 96 km/hr
• C. 32 km/hr
• D. $1\frac{2}{3}$ km/hr
• E. 16 km/hr

Answer 1

The correct option is C 32 km/hr


k=1/162;36/9=(1/162)⋅

$P=kA{V}^2$ ,$k=1/{16}^2$

now

$36/9=\left(1/{16}^2\right).\left(1\right).\left(v^2\right)$

v=$32$km/hr