JEE Mains · Physics · STD 11 - 5. work,energy,power and collision
The rain drop of mass \(1\) g, starts with zero velocity from a height of \(1\) km. It hits the ground with a speed of \(5\) m/s. The work done by the unknown resistive force is _______ J. (take \(g = 10\) m/s\(^2\))
- A \(-8.75\)
- B \(-8.35\)
- C \(-9.55\)
- D \(-9.98\)
Answer & Solution
Correct Answer
(D) \(-9.98\)
Step-by-step Solution
Detailed explanation
Using the work-energy theorem, the total work done by all forces equals the change in kinetic energy: \(W_{g} + W_{r} = \Delta K\) \(mgh + W_{r} = \dfrac{1}{2}mv^2 - 0\) Substituting the given values (\(m = 10^{-3}\) kg, \(g = 10\) m/s\(^2\), \(h = 1000\) m, \(v = 5\) m/s):…
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