A simple pendulum has a mass of 0.259 kg and a length of 0.97 m. It is displaced through an angle of 31.4 degrees and then released. After a time, the maximum angle of swing is only 10.0 degrees. How much energy has been lost to friction

The energy lost is 0.333156518 J.

Explanation:

The given mass of the pendulum = 0.259 kg

Length = 0.97 m

Displaced at an angle of = 31.4 degrees

Maximum angle of swing = 10 degrees

Initial potential energy = mgh

Initial potential energy = 0.259 × 9.8 × (1 – cos31.4)

= 0.259 × 9.8  × ( 1- 0.853551)

= 0.371716852 J

Final potential energy = mgh

Final potential energy = 0.259 × 9.8 × (1 – cos10)

= 0.259 × 9.8 × (1 – 0.984808)

= 0.0385603344 J

The lost energy =  Initial potential energy - Final potential energy  

= 0.371716852 J - 0.0385603344 J  

= 0.333156518 J

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