- 420 kN
- 280 kN
- 140 kN
- 90 kN
- 70 kN

Option 3 : 140 kN

Free

ST 1: Electric Network and Fields 1

6264

20 Questions
40 Marks
20 Mins

__Concept:__

Force exerted by the rocket exhaust (jet) on ground:

\(\\ {F_x} = \rho A{V^2} \)

Fx = Rate of change of momentum in the direction of the force

A = area of jet, V = velocity of jet

__Calculation:__

__Given:__

Diameter = 50 cm = 50 × 10-2 m, V = 1200 m/s, ρ = 0.5 kg/m3 o

\({F_x} = 0.5\times \frac{\pi }{4} \times {\left( {50 \times {{10}^{ - 2}}} \right)^2} \times {1200^2}\)

Fx = 141371 N = 141.371 kN

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