WTMA Springs and Elasticity 5

Question 1

If more coils are added to a coil spring while keeping the wire diameter and coil diameter the same, the spring becomes:

Accepted Answer

More flexible

Answer

More active coils means more material available to flex, reducing the spring constant and making the spring easier to deflect.

Question 2

If the wire diameter of a coil spring is doubled (keeping coil diameter and number of coils the same), the spring becomes:

Accepted Answer

Much stiffer

Answer

Spring stiffness increases with the fourth power of wire diameter, so doubling the wire diameter makes the spring about 16 times stiffer.

Question 3

Both a rubber band and a steel spring return to their original shape after being stretched. This shared property is called:

Accepted Answer

Elasticity

Answer

Elasticity is the ability of a material to return to its original shape after a deforming force is removed.

Question 4

If all dimensions are identical, which material would produce the stiffest spring?

Accepted Answer

High-carbon steel

Answer

High-carbon steel has the highest modulus of rigidity among these options, making springs from it the stiffest.

Question 5

Three springs, each with k = 30 lb/in, are connected in parallel and a 90-lb load is applied. How much does the assembly compress?

Accepted Answer

1 inch

Answer

Parallel total k = 30 + 30 + 30 = 90 lb/in; deflection = 90 lb / 90 lb/in = 1 inch.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test