Two masses, both equal to 100 g, are suspended at the ends of identical light strings of length ℓ = 1.0 m, attached to the same point on the ceiling. At time t = 0, they are simultaneously released from rest, one at angle θ₁ = 10°, the other at angle θ₂ = 20° from the vertical. The masses will collide
[Figure: Two pendulums with angles θ₁ and θ₂ from vertical]
(a) at θ = 0.0°, 0.50 s later.
(b) at θ = 5.0° to the right of the vertical, 0.16 s later.
(c) at θ = 0.0°, 0.13 s later.
(d) at θ = 5.0° to the right of the vertical, 0.10 s later.