Energy and Momentum – Rankers Physics

Momentum Conservation: Practice Problem & Solution

Assertion (A): A body with negative energy cannot have linear momentum. Reason (R): Magnitude of linear momentum can be negative.
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

Short Solution (Best for NEET):

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

Total mechanical energy \(E = K + U\) can be negative if potential energy \(U\) is negative and larger in magnitude than kinetic energy \(K\).


However, kinetic energy \(K = \frac{1}{2}mv^2\) is always non-negative, implying momentum exists. The magnitude of linear momentum \(|\vec{p}| = mv\) is always non-negative.


Therefore, both Assertion and Reason are false.

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