Garage facts & stats

Question 1

What does a spirit level show?

Accepted Answer

Whether a surface is level or plumb. A bubble centred between the lines shows a surface is horizontal (level) or vertical (plumb).

Question 2

Tyre pressure is often measured in psi. What does psi stand for?

Accepted Answer

Pounds per square inch. Psi measures pressure as pounds of force on each square inch.

Question 3

Why is running a car engine in a closed garage dangerous?

Accepted Answer

Exhaust contains carbon monoxide, an odourless poisonous gas. Carbon monoxide can build up quickly in enclosed spaces and cannot be seen or smelled.

Question 4

What does a torque wrench let you do?

Accepted Answer

Tighten a bolt to a set amount of turning force. Torque wrenches click or show a reading when the chosen torque is reached.

Question 5

A hydraulic car jack lifts heavy loads using which principle?

Accepted Answer

Pascal's principle. Pressure applied to a confined fluid is transmitted equally, so a small force can lift a big load.

Question 6

Which metal coats galvanised steel to protect it from rust?

Accepted Answer

Zinc. Zinc corrodes in preference to the steel underneath, protecting it.

Question 7

What type of spring on many overhead garage doors stores energy by twisting?

Accepted Answer

A torsion spring. Torsion springs above the door twist as it closes, storing energy that helps lift it.

Question 8

In an ideal lever, if the effort arm is twice as long as the load arm, what is the mechanical advantage?

Accepted Answer

2. Mechanical advantage equals effort arm divided by load arm, so twice the length doubles the force.

The basics