NEET · Physics · STD 11 - 4.1 newtons laws of motion

A shell of mass \(m\) is at rest initially. It explodes into three fragments having mass in the ratio \(2: 2: 1\). If the fragments having equal mass fly off along mutually perpendicular directions with speed \(v\), the speed of the third (lighter) fragment is :

A \(\sqrt{2} v\)
B \(2 \sqrt{2} v\)
C \(3 \sqrt{2} v\)
D \(v\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(2 \sqrt{2} v\)

Step-by-step Solution

Detailed explanation

By conservation of momentum : \(m(0)=\frac{2 m}{5}(-v \hat{i})+\frac{2 m}{5}(-v \hat{j})+\frac{m}{5} \vec{v}^{\prime}\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

The solids which have the negative temperature coefficient of resistance are :

NEET 2020 Easy

Match List \(I\) with List \(II\).

List \(I\) (Spectral Lines of Hydrogen for transitions from)	List \(II\) (Wavelengths (\(nm\)))
\(A\) \(n_2=3 \text { to } n_1=2\)	\(I\) \(410.2\)
\(B\) \(n_2=4 \text { to } n_1=2\)	\(II\) \(434.1\)
\(C\) \(n_2=5 \text { to } n_1=2\)	\(III\) \(656.3\)
\(D\) \(n_2=6 \text { to } n_1=2\)	\(IV\) \(486.1\)

Choose the correct answer from the options given below:

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