Explanation

Injection moulding is commonly used to produce plastic parts by injecting molten plastic into molds.

It allows high-volume, precise, and complex-shaped plastic products.

Explanation

Fine grains reduce the void spaces between particles, limiting fluid flow.

Coarse or rounded grains allow easier passage, so permeability is higher.

Explanation

A sump is a pit designed to collect water in excavations or basements.

It allows water to be pumped out, keeping the area dry and safe.

Explanation

Surge tanks are installed in pipelines to absorb sudden pressure changes caused by water hammer.

They protect pipes and pumps by reducing pressure surges in hydraulic systems.

Explanation

Perlite is an expanded volcanic glass used as lightweight aggregate in concrete, plaster, and insulation.

It improves thermal insulation and reduces concrete weight without compromising strength.

Explanation

Strain = ΔL / L

= (10 mm) / (500 cm)

= 10 mm / 5000 mm

= 0.002

Explanation

Friction is an unconservative force because it dissipates mechanical energy as heat.

Unlike conservative forces, work done depends on the path, not just initial and final positions.

Explanation

In neutral equilibrium, if the system is slightly displaced, it stays in the new position without returning or moving further.

Therefore, the potential energy remains constant at all positions.

Explanation

A beam with three fixed supports is statically indeterminate.

Each fixed support provides 3 reactions (vertical, horizontal, moment), so degree of indeterminacy = 3×3 – 3 (equations of equilibrium) = 6.

Explanation

Poisson’s ratio measures lateral expansion to axial compression; rubber is highly elastic, so it has the highest value (~0.5).

Metals like steel, copper, cast iron have much lower Poisson’s ratios (0.25–0.35).