Question

An aeroplane flying horizontally with a speed of 360 km^-1 releases a bomb at a height of 490 m from the ground. If g = 9.8 m s^-2, it will strike the ground at

• A. 10 km
• B. 100 km
• C. 1 km
• D. 16 km

Answer 1

Answer: (C)

1 km

Answer 2

Time taken by the bomb to fall through a height of 490 m

$t = \sqrt{\frac{2h}{g}} = \sqrt{\frac{2 \times 490}{9.8}} = 10s$

Distance at which the bomb strikes the ground

= horizontal velocity × time

= $360kmh^{- 1} \times 10s$

$= 360kmh^{- 1} \times \frac{10}{3600}h = 1km$