JEE Mains · Physics · STD 11 - 5. work,energy,power and collision
A small block slides down from the top of hemisphere of radius \(R=3\, {m}\) as shown in the figure. The height \('h'\) at which the block will lose contact with the surface of the sphere is \(............. \;\;m\). (Assume there is no friction between the block and the hemisphere)
- A \(1\)
- B \(2\)
- C \(3\)
- D \(4\)
Answer & Solution
Correct Answer
(B) \(2\)
Step-by-step Solution
Detailed explanation
on balancing \(m g \cos \theta=\frac{m v^{2}}{R}....(1)\) \(\cos \theta=\frac{h}{R}\) Energy conservation \(m g\{R-h\}=\frac{1}{2} m v^{2}....(2)\) From \((1)\) and \((2) \Rightarrow m g\left\{\frac{h}{R}\right\}=\frac{2 m g\{R-h\}}{R}\) \(h=\frac{2 R}{3}=2\, m\)
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