A pendulum is suspended by a string of length 250 cm. The mass of the bob of the pendulum is 200g. The bob is pulled aside until the string is at 60° with vertical as shown in the figure. After releasing the bob, the maximum velocity attained by the bob will be_________ ms^-1. (if g = 10m/s²)

From conservation of Energy:

$mg\mathcal{l}\left(1-cos60°\right)=\frac{1}{2}m{v}^2$

$\Rightarrow v^2=2g\mathcal{l}\left(\frac{1}{2}\right)=g\mathcal{l}$

$=10\times \frac{25}{10}=5m/s$

<p>From conservation of Energy:</p><div><div><picture><source srcset="" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/1752229118phpfvlHSJ.jpeg" alt="" width="145" height="135" loading="lazy"></picture></div></div><p><math><mrow><mi>m</mi><mi>g</mi><mi mathvariant="script">l</mi><mrow><mo> (</mo><mrow><mn>1</mn><mo>−</mo><mi>c</mi><mi>o</mi><mi>s</mi><mn>6</mn><mn>0</mn><mo>°</mo></mrow><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mi>m</mi><msup><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></p><p><math><mrow><mo>⇒</mo><msup><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>2</mn><mi>g</mi><mi mathvariant="script">l</mi><mrow><mo> (</mo><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow><mo>)</mo></mrow><mo>=</mo><mi>g</mi><mi mathvariant="script">l</mi></mrow></math></p><p><math><mrow><mo>=</mo><mn>1</mn><mn>0</mn><mo>×</mo><mfrac><mrow><mn>2</mn><mn>5</mn></mrow><mrow><mn>1</mn><mn>0</mn></mrow></mfrac><mo>=</mo><mn>5</mn><mi>m</mi><mo>/</mo><mi>s</mi></mrow></math></p>

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