Question

Which of the following statement is correct in connection with projectiles?

• A. A path traced by a projectile in space is known as trajectory.
• B. The velocity with which a projectile is projected is known as velocity of projection.
• C. The angle with the horizontal at which a projectile is projected is known as angle of projection.
• D. all of the above

Hint:

The horizontal component of the velocity of projection ($u \cos \alpha$) always remains constant throughout the flight because there is no horizontal force (like air resistance) acting on it.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Projectile motion is a form of motion experienced by an object or particle (a projectile) that is thrown near the Earth's surface and moves along a curved path under the action of gravity only.

Step 2: Detailed Explanation:

• Trajectory: This is the specific parabolic curve that the object follows through the air.
• Velocity of Projection ($u$): The initial speed given to the object at the starting point.
• Angle of Projection ($\alpha$): The specific angle relative to the horizontal ground at which the object is launched. Since all three definitions are standard and correct in physics, option (D) is the correct choice.

Step 3: Final Answer:
All the provided statements regarding projectiles are correct.

Answer 2

This question asks which statement about projectile motion terminology is correct. Since this is a "which of the following" type question, let's verify each individual statement on its own merits.

1. A path traced by a projectile in space is known as trajectory: This is a standard and accurate definition. When an object is launched into the air and moves under gravity alone, the curved path it follows, typically parabolic near the Earth's surface, is universally called its trajectory. This statement is true.
2. The velocity with which a projectile is projected is known as velocity of projection: This is also a correct, standard definition. The initial speed and direction imparted to the object at the instant it is launched is called the velocity of projection, often denoted \( u \), and it remains the fixed reference value used throughout the analysis of the motion.
3. The angle with the horizontal at which a projectile is projected is known as angle of projection: This statement is correct as well. The angle measured from the horizontal ground level to the initial direction of launch is called the angle of projection, commonly denoted \( \alpha \), and it determines how the initial velocity splits into horizontal and vertical components.
4. All of the above: Since each of the first three statements independently describes a correct, standard term used in projectile motion, none of them contain any error, so the option combining all three fully captures the true state of affairs.

Because every individual statement checks out as an accurate, standard definition in projectile motion, none can be singled out as false, meaning the comprehensive option is the right choice.

Therefore, the correct answer is all of the above.