Verified Solution • 2025–26 Session moderate

Q5.18: NCERT Physics - Part 1 WORK, ENERGY AND POWER 5.18 Solution: The bob of a pendulum is released from a horizontal position.…

The bob of a pendulum is released from a horizontal position. If the length of the pendulum is 1.5 m, what is the speed with which the bob arrives at the lowermost point, given that it dissipated 5% of its initial energy against air resistance?

Step-by-Step Verified Solution

**Answer:** v = 5.3 m/s **Step-by-Step Explanation:** Initial potential energy = mgh = mgL (since released from horizontal position). 5% energy dissipated, so 95% converted to kinetic energy:
0.95mgL=12mv20.95mgL = \frac{1}{2}mv^2
v=2×0.95×g×L=1.9×10×1.5=28.5=5.34 m/sv = \sqrt{2 \times 0.95 \times g \times L} = \sqrt{1.9 \times 10 \times 1.5} = \sqrt{28.5} = 5.34 \text{ m/s}

All Questions in this Chapter

Q5.1 Q5.2 Q5.3 Q5.4 Q5.5 Q5.6 Q5.7 Q5.8 Q5.9 Q5.10 Q5.11 Q5.12 Q5.13 Q5.14 Q5.15 Q5.16 Q5.17 Q5.18 Q5.19 Q5.20 Q5.21 Q5.22 Q5.23

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