physics of springs

1. SPRINGS
• DEFINATION:
The spiral springs are used to either
resist or to assist the force of muscular
contraction OR to produce passive movement of
joints.
FORMATION:
A spring is consist of a uniform coil of
wire which is extensible .

2. The Extensibility Of Spring:
A spring can be elongated by a
force applied at one end in the direction of its long axis , the
other end is being fixed
The increase in the length is directly
proportional to the magnitude of force
Weight of Spring:
 Springs are graded in pounds 40lbs,20lbs
 A tape is inserted within spring ,the tape become taut when
maximum length is reached .
 Weight of a spring is determined by
1. The material of wire
2. Thickness of wire
3. Diameter of coils

3. The Recoil:
 when applied force is removed the spring will return to
its original length
 Potential energy is stored during extension
 Kinetic energy is released when spring return to its
original length
Oscillatory movements:
if a weight applied to a stretch a
spring is raised and then released again oscillatory
movement is produced ,the amplitude of which decrease
progressively until it comes to rest

4. Spring used In Parallel
 When a spring of a specific weight is not available two
springs of half the required weight may be used in
parallel
 Two 40-lb springs arranged in parallel act as 80-lb
 In the case of two parallel springs double force in
required to elongate springs
 In parallel the springs extend half the
amount compared to what
would have happened with just one.
For 40-Ib springs arranged in parallel ,
80-Ib force is required

5. Springs used in series
 The weight of two equal springs arranged in series
act as a single spring.
 In this case half force is required to elongate springs.
 Each of two springs are only half extended.
The amount by which they must be extended in order
to reach its limit of extension is double.
For 40-Ib springs arrange in
series 20-Ib force is required