The weight of the mathematical pendulum L = 2.9 m long was deflected at an angle α = 51

The weight of the mathematical pendulum L = 2.9 m long was deflected at an angle α = 51 ° from the vertical and released without a push. Find the speed of the load V at the lowest point of the trajectory. Give your answer in m / s and round to two decimal places.

With respect to the balance point, the load was raised to a height:
H = L – L * cosα;
According to the law of conservation of energy, the potential energy at the upper point is equal to the kinetic energy at the lower point:
m * g * H = m * (v ^ 2) / 2;
v = sqrt (2 * g * H) = sqrt [2 * g * L (1 – cosα)];
v = sqrt (20 * 2.9 * 0.37) = 3.28m / s