Question

Assertion: In a plane to plane projectile motion, the horizontal components of velocity remain constant.

Reason: In a plane to plane projectile motion, the horizontal component of acceleration is zero.

• A. both assertion and reason are true and reason is the correct explanation of assertion.
• B. both assertion and reason are true but reason is not the correct explanation of assertion.
• C. assertion is true but reason is false.
• D. assertion is false but reason is true.

Answer 1

The correct option is A

both assertion and reason are true and reason is the correct explanation of assertion.

Explanation for assertion statement:

The diagrammatic representation of the plane to plane projectile motion of a projectile is given below:

1. Here, $u$ is the velocity of the projectile, $u_x$ is the horizontal component and $u_y$ is the vertical component of the velocity of the projectile at an instant.
2. Here, $\theta$ is the angle of projection and $A$ is the point where the projectile has the maximum height.
3. The horizontal component of the projectile remains constant throughout the motion.
4. The value of the horizontal component of the velocity is $u_x=u\cos \theta$
5. Therefore, the assertion is true.

Explanation for reason statement:

1. The only acceleration acting on the projectile is gravity. Hence, the direction of acceleration will be downwards.
2. Thus, no acceleration is acting in the horizontal direction which is why the horizontal component of the motion remains constant.
3. Therefore, the reason is true and the correct explanation of the assertion.

Hence, option A is the correct answer.