Question

Abomb is dropped from an aeroplane flying horizontally with a velocity of 720km at an altitude of 980m. Time taken by the bomb to hit the ground is
1) 1s
2) 7.2s
3) 14.14s
4) 0.15s​

Answer 1

Given :

Velocity of the plane = 720km/hr

Height of plane = 980m

To Find :

Time taken by bomb to hit the ground.

Solution :

❖ This question is based on the concept of height to ground projectile.

Initial downward velocity of bomb is zero.

Since constant acceleration due to gravity acts on the bomb, equation of kinematic can be used to solve this question$.$

• For an object falling freely under the action of gravity, g is taken positive.

Second equation of kinematics is given by

➙ h = ut + 1/2 gt²

• h denotes height
• g denotes acceleration
• t denotes time
• u denotes initial velocity

By substituting the given values;

➙ 980 = (0 × t) + 1/2 (9.8) t²

➙ 980 × 2/9.8 = t²

➙ t² = 200

➙ t = √200

➙ t = 14.14 s

Answer 2

$\huge\colorbox{yellow}{Áηѕωєя࿐❤}$

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Given :

Velocity of the plane = 720km/hr

Height of plane = 980m

To Find :

Time taken by bomb to hit the ground.

Solution :

❖ This question is based on the concept of height to ground projectile.

Initial downward velocity of bomb is zero.

Since constant acceleration due to gravity acts on the bomb, equation of kinematic can be used to solve this question..

• For an object falling freely under the action of gravity, g is taken positive.

Second equation of kinematics is given by

➙ h = ut + 1/2 gt²

• h→denotes height
• g→denotes acceleration
• t →denotes time
• u→denotes initial velocity

By substituting the given values;

➙ 980 = (0 × t) + 1/2 (9.8) t²

➙ 980 × 2/9.8 = t²

➙ t² = 200

➙ t = √200

➙ t = 14.14 s

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Hope it helps :)