ADF ADF Mechanical Reasoning

Question 1

Gear A has 20 teeth and meshes with Gear B which has 10 teeth. If Gear A completes one full rotation, how many rotations does Gear B complete?

Accepted Answer

Two rotations

Answer

Gear ratio equals the driver's tooth count divided by the driven gear's; 20 ÷ 10 = 2, so Gear B completes two rotations for every one rotation of Gear A.

Question 2

Which class of lever has the effort force applied between the fulcrum and the load?

Accepted Answer

Third-class lever

Answer

A third-class lever places the effort between the fulcrum and the load; tweezers and a fishing rod are common examples.

Question 3

A system uses one fixed pulley and one movable pulley. By what factor does this reduce the force needed to lift a load?

Accepted Answer

Force is reduced by half

Answer

A compound pulley with one fixed and one movable pulley gives a mechanical advantage of 2, halving the required effort force.

Question 4

Water flows through a pipe that suddenly narrows. What happens to the water's velocity in the narrower section?

Accepted Answer

Velocity increases

Answer

The continuity principle states that for an incompressible fluid, flow rate is constant, so velocity must increase when the cross-sectional area decreases.

Question 5

Of the following materials, which is the best conductor of electricity?

Accepted Answer

Copper

Answer

Copper has very low electrical resistance and abundant free electrons, making it the standard material for electrical wiring.

ADF - Australian Defence Force Practice Test

ADF - Australian Defence Force Practice Test

ADF ADF Mechanical Reasoning