Question

A forward horizontal force of 12 N is used to pull a 240-N crate at constant velocity across a
horizontal floor. The coefficient of friction is:

Answer 1

Explanation:

$let \: coefficient \: of \: friction \: be \: \gamma \\ from \: third \: law \: of \: solid \: friction \\friction \: force = \gamma \times normal \: reaction \\ F = \gamma R \\ but \: R = mg = 240N \\ \gamma = \frac{ F}{R} \\ \gamma = \frac{12}{240} \\ \gamma = \frac{1}{20}$