Springs and Elasticity Flashcards

A spring stretches 3 inches when a 15-lb weight is hung from it. How far will it stretch with a 25-lb weight?

Answer: 5 inches

The spring constant is 15/3 = 5 lb/in, so a 25-lb load stretches it 25/5 = 5 inches.

If two identical springs (each with spring constant k) are connected in parallel, what is the combined spring constant?

Answer: 2k

Springs in parallel add their constants directly, so the combined constant is k + k = 2k.

A spring is stretched beyond its elastic limit. What happens when the force is removed?

Answer: It stays partially stretched

Once the elastic limit is exceeded, the spring undergoes permanent (plastic) deformation and will not fully recover.

Which of the following best describes a spring with a high spring constant?

Answer: It requires large force for small deflection

A high spring constant (k) means the spring is stiff — it resists deformation and requires a large force to stretch or compress it a small amount.

A mechanic cuts a coil spring in half. What happens to the spring constant of each half?

Answer: It is doubled

Fewer active coils means less flexibility, so cutting a spring in half doubles its spring constant.

A spring scale used to weigh objects operates on which principle?

Answer: Hooke's Law

A spring scale uses Hooke's Law — the deflection of the spring is proportional to the applied force (weight).

Two identical springs (spring constant k each) are connected end-to-end in series. What is the combined spring constant?

Answer: k/2

Springs in series have a combined constant of 1/(1/k + 1/k) = k/2, making the assembly more flexible than either spring alone.