F.2 Forces and Hooke's Law

Practice Worksheet — name: ______________________ date: ____________

Formulas for this topic

Hooke's Law (restoring force)

F = -kx

Newton's Second Law

F_{net} = ma

Section A — Multiple choice

A1. A spring with a constant of 50 N/m is stretched by 0.1 meters. What restoring force is exerted by the spring?

A $5\, N$
B $50\, N$
C $500\, N$
D $0.2\, N$

A2. Which of the following is a non-contact force?

A Frictional force
B Tension
C Air resistance
D Gravitational force

Section B — Short answer

B1. Explain Hooke's Law and define the terms in the formula $F = -kx$ .

B2. What is the net force acting on an object traveling at a constant velocity?

Answer key

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Section A

A1: $5\, N$

A2: Gravitational force

Section B

B1: Hooke's Law states that the extension of a spring is directly proportional to the force applied to it, within its elastic limit. In the restoring force formula $F = -kx$ , $F$ is the restoring force, $k$ is the spring constant, and $x$ is the extension/displacement.

B2: The net force is zero Newtons ( $0\, N$ ). Constant velocity implies acceleration is zero, and by Newton's Second Law ( $F = ma$ ), net force must be zero.