Assertion : A projectile should have two component velocities in two mutually perpendicular directions .
Reason : A body is said to be projectile if it has motion in two dimensions.

Answer

To analyze the given assertion and reason, let's break it down step by step.

### Step 1: Understanding the Assertion
The assertion states that "A projectile should have two component velocities in two mutually perpendicular directions."

- In projectile motion, an object moves under the influence of gravity after being projected. The motion can be analyzed in two dimensions: horizontal (x-direction) and vertical (y-direction).
- The initial velocity of the projectile can be resolved into two components:
- Horizontal component: \( u \cos \theta \)
- Vertical component: \( u \sin \theta \)

Thus, the assertion is **correct** because a projectile indeed has two component velocities in mutually perpendicular directions.

### Step 2: Understanding the Reason
The reason states that "A body is said to be a projectile if it has motion in two dimensions."

- While it is true that projectiles move in two dimensions, not all two-dimensional motions are classified as projectile motions. For example, uniform circular motion is also a two-dimensional motion but is not considered projectile motion.
- Therefore, the reason is **false** because having motion in two dimensions does not necessarily mean the body is a projectile.

### Conclusion
- The assertion is correct.
- The reason is false.

### Final Answer
- Assertion: Correct
- Reason: False

---