SITEMAP   School-college Physics Notes: Forces Section 4.2 Elasticity and work done

UK GCSE level age ~14-16 ~US grades 9-10 Scroll down, take time to study content or follow links

Forces 4: 4.2 Work is done in stretching or compressing a material and elastic potential energy may stored or absorbed - shock absorbers

Doc Brown's Physics exam study revision notes

4.2 Work is done in stretching or compressing a material

Why does stretching a spring involve doing work?

In the process of bending, stretching or compressing, energy is transferred in the process, so work is done.

You are having to do work against an opposing force e.g. a stretched spring or rubber band, a squeezed rubber ball want to return to their original shape

In order to deform a material to be bent, stretched or compressed two forces must be operating, often in opposite directions.

If only one force was involved the material would stay the same shape and just change position.

Bending occurs when you wind up a mechanical clock. Strictly speaking on the 'outer' surface to the right the force is one of tension (stretching) and the 'inner' surface to the left, experiences compression (think of bending quite a thick plate, ok?).

Stretching happens when you use a spring balance to weigh something or put a rubber band round an object.

Older (still do?) forms of car suspension use steel springs which compress on meeting a bump in the road to absorb the energy of the impact.

Rubber shock absorbers in the under carriage of a car have the same effect.

The large sturdy spring S of the wheel suspension of a Land Rover, which is expected to absorb the impact energy of some pretty hefty bumps! On compression, the stiff spring will store a great deal of elastic energy, if only for a brief moment in time!

Key for the 5 photographic diagrams: S = suspension spring;  H = the pipe conveying the hydraulic brake fluid (see hydraulics)

D = the brake drum and disc on which the brake pads in casing P are forced into contact with the smooth disc by hydraulic pressure when you press the brake pedal.

A double spring suspension on a red van, conveniently jacked up!

'Spring' photographs by courtesy of Mark Raw of M T R Autotech Ltd garage, Castleton, North Yorkshire, England

Keywords, phrases and learning objectives for elastic potential energy

Be able to explain why work is done in stretching or compressing a material and elastic potential energy may stored or absorbed e.g. in car suspension springs or shock absorbers.

WHAT NEXT?

INDEX for physics notes on FORCES section 4

email doc brown - comments - query?

BIG website, using the [SEARCH BOX] below, maybe quicker than navigating the many sub-indexes

for UK KS3 science students aged ~12-14, ~US grades 6-8

ChemistryPhysics for UK GCSE level students aged ~14-16, ~US grades 9-10

for pre-university age ~16-18 ~US grades 11-12, K12 Honors

Use your mobile phone in 'landscape' mode?

SITEMAP Website content © Dr Phil Brown 2000+. All copyrights reserved on Doc Brown's physics revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries and references to GCSE science course specifications are unofficial.

Using SEARCH some initial results may be ad links you can ignore - look for docbrown

 @import url(https://www.google.co.uk/cse/api/branding.css); ENTER specific physics words or courses e.g. topic, module, exam board, formula, concept, equation, 'phrase', homework question! anything of physics interest!  This is a very comprehensive Google generated search of my website

TOP OF PAGE