Question

42. An aeroplane is flying at a height of 1960 m in
horizontal direction with a velocity of 360 km/hr.
When it is vertically above the point A on the
ground, it drops a bomb. The bomb strikes a point
B on the ground, then the time taken by the bomb
to reach the ground is-
(1) 2012 sec
(2) 20 sec
(3) 10.2
sec
(4) 10 sec​

Answer 1

Answer:

20 s

Explanation:

Along vertical direction

Initial velocity of bomb = 0 m/s

Height from which it is dropped = 1960 m

Then, from equation of motion, s = ut + 0.5at²

1960 m = (0 m/s × t) + (0.5 × 9.8 m/s² × t²)

t² = 1960 m / (4.9 m/s²)

t = sqrt(1960/4.9) s

t = sqrt(400) s

t = 20 s