Projectile Motion and Energy Conservation – Rankers Physics

Potential Energy & Equilibrium: Practice Problem & Solution

Assertion (A): Two balls of different masses are thrown vertically upwards with same speed. They will pass through their point of projection in the downward direction with the same speed in absence of air resistance. Reason (R): In absence of air resistance, the mechanical energy of a projectile is conserved.
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Potential Energy & Equilibrium. Understanding the underlying formula is key to arriving at the correct answer below:

In the absence of air resistance, only gravity acts, a conservative force. Thus, mechanical energy is conserved. This implies that the speed at any height (including projection point) is the same, irrespective of mass.

Both Assertion and Reason are true, and Reason correctly explains Assertion.

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