Answer:
how fast it is moving in m/s? 0.65 m/s.
Explanation:
given information:
the length of the arm, L - 0.9 m
angle, θ = 20°
First we calculate the distance in horizontal motion
s = 2 L sin θ
= 2 (0.9) sin 20°
= 0.62 m
now calculate the time
t/2 = 2π√(L/g)
t = π√(0.9/9.8)
= 0.95 s
the speed is
v = s/t
= 0.62/0.95
= 0.65 m/s