Hooke's Law

If F is force, k is spring constant and x is extension, Hooke's Law tells us that:

• F=k/x
• x=Fk
• k=Fx
• F=kx

Hooke's Law fails when a material reaches its:

• breakdown

• elastic limit

• limit of proportionality

• fracture stress

A graph of extension against force for an elastic material is:

• A downward curve
• An upward curve
• A straight line from any point on the x and y axis
• A straight line from the origin

A stiff material has a:

• high spring constant
• low spring constant
• spring constant of any value
• spring constant which is difficult to predict

A spring has a spring constant of 5N/cm.  What is its extension when loaded with 15N?

• 4cm
• 5cm
• 3m
• 3cm

A spring extends 1.5m under load 10N. What is its spring constant?

• 0.15N/m
• 10N/m
• 6.7N/m
• 15N/m

A 25,000 N Car is supported by 4 springs. If each spring is deflected by 0.040 m what is the spring constant? (Think about how much weight each spring holds up!)

• 160,000 N /m

• 620,000 N/m

• 630,000 N/m

• 120,000 N/m

A net force of 430 N acts to stretch an extension spring.  How far will the spring stretch if its spring constant is 700 N/m?

• 43.9
• 0.307 m
• 1.63 m
• 0.614 m

Which statement most accurately represents Hooke's Law?

• Extension of a spring is proportional to the force applied.

• Extension of a spring is proportional to the number of coils.

• Extension of a spring is inversely proportional to the force applied.

• Thickness of a spring wire is proportional to the force applied.

Spring constant is measured in

• N

• N/m

• m