Physics is required to solve the first part of this challenge.
The challenge begins with massless pivot anchored to the ground. Connected to the pivot by two unbending metal rods a fixed third rotation apart are a weight and another massless pivot. The weight is 5 cm from the centre, the other pivot, 3 cm. The pivot is clockwise of the weight. Attached to the second pivot, there is also another wight, attached by another unbending rod, this one of length 3 cm. The first weight weighs 5 kilograms, the second, three. A force of 1 newton is applied for 1 second to the first weight, perpendicular to the metal rod, to make the system rotate counterclockwise. The challenge is to determine how many rotations per minute it will spin at.