MHT CET · Physics · Work Power Energy

The work done by a force on body of mass \(5 \mathrm{~kg}\) to accelerate it in the direction of force from rest to \(20 \mathrm{~m} / \mathrm{s}\) in 10 second is

A \(2 \times 10^3 \mathrm{~J}\)
B \(10^3 \mathrm{~J}\)
C \(10^{-3} \mathrm{~J}\)
D \(4 \times 10^3 \mathrm{~J}\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(10^3 \mathrm{~J}\)

Step-by-step Solution

Detailed explanation

The correct option is (B).
Concept: According to the work-energy theorem:
Total work done by all forces (conservative or non - conservative) \(=\) Change in K.E.
\(\mathrm{W}=\frac{1}{2} \mathrm{mv}^2=\frac{1}{2} \times 5 \times 20^2=10^3 \mathrm{~J}\)

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.

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