Wire under tension
A 1.500 m wire becomes 1.5075 m long under load. Find extension and percentage extension.
TOPIC 6 · CIE PRACTICEDefine the specimen.
Define the specimen.
Read the graph.
Attempt each visible question, open a modelling hint if needed, then reveal the detailed solution.
Two springs
Springs of 200 N m⁻¹ and 300 N m⁻¹ each carry 12 N. Compare their extensions.
Interpreting gradient
A force–extension graph is straight from (0,0) to (0.030 m, 9.0 N), then curves. Find k and identify the significance of the end of the straight section.
Permanent extension
A wire is loaded to 16 N and extends 4.0 mm. After unloading it remains 0.8 mm longer. Explain what happened.
Spring launcher
A 180 N m⁻¹ spring is compressed 0.075 m and launches a 0.20 kg object with 70% efficiency. Find launch speed.
Testing a wire
A wire of area 1.5 × 10⁻⁶ m² and original length 2.0 m carries 120 N and extends 1.2 mm. Find stress and strain.
Material stiffness
Use the wire data from question 6 to find Young modulus. Predict the extension if length doubles while force and area stay fixed.