a. The frequency should be 0.614Hz
b The pendulum bob's speed is 0.443 m/s
c. The total energy stored is 0.0304 J
a. The frequency should be
Here we have to first apply the periodic time
T= 2π√(L/g)
Now the frequency should be
= 1/T (Hz)
T = 2 × 3.14 √ (0.66/9.81)
= 6.28 × √0.0673
1.6289 Seconds
Now
Frequency = 1/T
= f = 1/1.6289
= 0.614 Hz
b) The speed of the bob is
Here the vertical distance via the height is
h= 0.66 cos 12
h = 0.65 m
Now
Vertical fall at the lowest point should be
= 0.66 - 0.65
= 0.01 m
Now
energy lost (MgΔh) = KE gained (1/2mv²)
mgh = 1/2mv²
v² = 2gΔh = 2×9.81 × 0.01
= 0.1962
So, v = 0.443 m/s
c) The total energy is
E = 1/2mv²
= 1/2 × 0.310 × 0.443²
= 0.0304 J
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