OAR Mechanical Comprehension exam 2023 with 100% correct answers

What is a lever? A simple machine that provides a mechanical advantage in carrying loads. Composed of a fulcrum (or pivot) and rigid rod (or beam). What is the formula for calculating the load or the effort of a lever? W1 x L1 = W2 x L2 (Weight of the load x distance of the load from the fulcrum = weight of the effort x distance from the fulcrum to the effort.) What is a first class lever? A lever where the fulcrum is located between the force and the load. ie. seesaw What is a second class lever? A lever where the load (weight) is located between the force (or effort) and fulcrum. ie. wheelbarrow, bottle opener, nutcracker. Best suited for carrying heavy loads. What is a third class lever? A lever where the force is located between the load and the fulcrum. ie. chopsticks, tweezers. Used for accuracy rather than weight. What is a gear? A wheel with equally sized and spaced teeth located on the circumference. What is the first rule of thumb in meshed gears? Adjacent gears rotate in opposite directions. If a gear system has an even number of cogwheels then...? The last cogwheel will turn in the direction opposite the first wheel.