Area 3: Mechanisms and structures

An SQA National 5 Engineering Science answer on forces, covering the difference between mass and weight, the weight relationship W equals mg, the force-mass-acceleration relationship F equals ma, and balanced and unbalanced forces in an engineering context.

An SQA National 5 Engineering Science answer on gear systems, covering the gear ratio as the ratio of driven to driver teeth, calculating output speed, how a gear train trades rotational speed for turning force (torque), and the direction reversal between meshing gears.

An SQA National 5 Engineering Science answer on levers and moments, covering the moment of a force as force times perpendicular distance, the principle of moments for a balanced lever, and how a lever provides a mechanical advantage to lift a large load with a smaller effort.

An SQA National 5 Engineering Science answer on materials, covering the main mechanical properties such as strength, hardness, toughness, ductility and elasticity, the main groups of engineering materials, and how an engineer selects a material to suit the forces and conditions of a structural job.

An SQA National 5 Engineering Science answer on mechanical advantage, velocity ratio and efficiency, covering mechanical advantage as load over effort, velocity ratio, the percentage efficiency relationship, and why a real machine's efficiency is always below 100% because of friction.

An SQA National 5 Engineering Science answer on mechanisms and drive systems, covering the four types of motion, belt and chain drives and where each is used, and calculating the velocity ratio and output speed of a pulley system from the pulley diameters.

An SQA National 5 Engineering Science answer on pressure and pneumatics, covering pressure as force per unit area, the relationship P equals F over A, the units of pressure, and how a pneumatic cylinder converts air pressure acting on a piston into a useful output force.

An SQA National 5 Engineering Science answer on structures, covering tension and compression in members, the difference between a tie and a strut, the equilibrium of a loaded beam, and using the principle of moments and balanced forces to calculate the support reactions of a simply supported beam.

An SQA National 5 Engineering Science answer on work, energy and power, covering work done as force times distance, energy transferred equal to work done, mechanical power as work done per second, and the relationships needed to calculate each in an engineering context.