Which of the following motions is different from others ?

Options

A. A ball throw horizontally in air .
B. A bomb released from a flying aeroplane .
C. A jevelin thrown by an athlete.
D. A bird flying in the air .

Answer

To determine which of the following motions is different from the others, we need to analyze each option:

1. **A ball thrown horizontally in air**:
- When a ball is thrown horizontally, it has an initial horizontal velocity. As it moves, it is also affected by gravity, which causes it to accelerate downwards. This results in a curved path known as projectile motion.

2. **A bomb released from a flying aeroplane**:
- Similar to the ball, when a bomb is released from a moving aeroplane, it retains the horizontal velocity of the aeroplane. It also experiences the acceleration due to gravity, causing it to follow a parabolic trajectory. This is also classified as projectile motion.

3. **A javelin thrown by an athlete**:
- When an athlete throws a javelin, it is projected at an angle. The javelin has both horizontal and vertical components of velocity. Due to gravity, it will follow a parabolic path until it lands, which is again a type of projectile motion.

4. **A bird flying in the air**:
- A bird flying in the air typically moves in a straight line and can adjust its path as needed. Unlike the previous three motions, the bird's motion does not follow a parabolic trajectory and is not influenced by gravity in the same way. It can be considered as translatory motion.

### Conclusion:
The motion that is different from the others is **the bird flying in the air**. The first three options (the ball, the bomb, and the javelin) are all examples of projectile motion, while the bird's flight is a straight-line motion.

### Step-by-Step Solution:
1. **Analyze the motion of the ball thrown horizontally**:
- It follows a projectile motion due to gravity acting on it.

2. **Analyze the motion of the bomb released from an aeroplane**:
- It also follows projectile motion as it retains the horizontal speed of the plane and is affected by gravity.

3. **Analyze the motion of the javelin thrown by an athlete**:
- The javelin follows projectile motion, having both horizontal and vertical components.

4. **Analyze the motion of the bird flying in the air**:
- The bird flies in a straight line, which is translatory motion, not influenced by gravity in the same manner.

5. **Identify the different motion**:
- The bird's motion is different from the projectile motions of the other three options.