JEE Mains · Physics · STD 11 - Work,energy,power and collision
- JEE Mains 2026
- Medium
- MCQ
A body of mass \(1\) kg moves along a straight line with a velocity \(v = 2x^2\). The work done by the body during displacement from \(x = 0\) to \(5\) m is __________ J.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(1250\)
Step-by-step Solution
Detailed explanation
Given mass \(m = 1\) kg and velocity \(v = 2x^2\).
According to the work-energy theorem, the work done by the net force is equal to the change in kinetic energy of the body.
\(W = \Delta K = K_f - K_i\)
At \(x = 0\) m, initial velocity \(v_i = 2(0)^2 = 0\) m/s.
At \(x = 5\) m, final velocity \(v_f = 2(5)^2 = 50\) m/s.
Initial kinetic energy \(K_i = \dfrac{1}{2} m v_i^2 = 0\) J.
Final kinetic energy \(K_f = \dfrac{1}{2} m v_f^2 = \dfrac{1}{2} \times 1 \times (50)^2 = 1250\) J.
Work done \(W = 1250 - 0 = 1250\) J.
Answer: \(1250\)
According to the work-energy theorem, the work done by the net force is equal to the change in kinetic energy of the body.
\(W = \Delta K = K_f - K_i\)
At \(x = 0\) m, initial velocity \(v_i = 2(0)^2 = 0\) m/s.
At \(x = 5\) m, final velocity \(v_f = 2(5)^2 = 50\) m/s.
Initial kinetic energy \(K_i = \dfrac{1}{2} m v_i^2 = 0\) J.
Final kinetic energy \(K_f = \dfrac{1}{2} m v_f^2 = \dfrac{1}{2} \times 1 \times (50)^2 = 1250\) J.
Work done \(W = 1250 - 0 = 1250\) J.
Answer: \(1250\)
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