{"id":"mechanical-aptitude-free","timeLimitSec":167,"questions":[{"id":"maf-001","section":"lever","q":"A straight bar rests on a fulcrum. A 300 N load sits 0.5 m from the fulcrum on one side, and you push down 1.5 m from the fulcrum on the other side. What force balances the load?","options":["300 N","150 N","100 N","900 N"],"answer":2,"explain":"Moments balance: effort x 1.5 m = 300 N x 0.5 m, so effort = 150 / 1.5 = 100 N."},{"id":"maf-002","section":"pulley","q":"A rope runs over a single fixed pulley attached to the ceiling and lifts a 100 N load. Ignoring friction, what pull on the rope holds the load?","options":["200 N","25 N","50 N","100 N"],"answer":3,"explain":"A single fixed pulley only changes the direction of the force. Its mechanical advantage is 1, so you pull 100 N."},{"id":"maf-003","section":"fluid","q":"In a hydraulic press, the small piston has an area of 2 cm² and the large piston 50 cm². A 40 N force pushes the small piston. What force does the large piston exert?","options":["80 N","1,000 N","2,000 N","1.6 N"],"answer":1,"explain":"The pressure is the same on both pistons, so the force scales with area: 40 x 50 / 2 = 1,000 N."},{"id":"maf-004","section":"gear","q":"Gear A with 20 teeth drives gear B with 40 teeth. Gear A turns at 120 rpm. How fast does gear B turn?","options":["60 rpm","30 rpm","120 rpm","240 rpm"],"answer":0,"explain":"Speed scales inversely with teeth: 120 x 20 / 40 = 60 rpm. The bigger gear turns slower."},{"id":"maf-005","section":"elec","q":"A 12 V battery is connected across a 4-ohm resistor. How much current flows?","options":["3 A","0.33 A","48 A","16 A"],"answer":0,"explain":"Ohm's law: current = voltage / resistance = 12 / 4 = 3 amperes."}]}