Question

a force of 10 N acts on a mass of 5 kg producing an acceleration of 1.5 m/s^2 what is the magnitude of the force of friction acting on the mass

Answer 1

Explanations & Calculations

• if the friction force is $\small f$, then following the definition of Newton's second law, you can calculate the friction force.

$\qquad\qquad \begin{aligned} \small \Sigma F&=\small ma\\ \small 10\,N-f&=\small 5\,kg\times1.5\,ms^{-2}\\ \small f&=\small 2.5\,N \end{aligned}$

• The net force is considered when substituting for the force in this equation.
• Under the influence of all these forces, the object still accelerates meaning that the applied force is larger than the friction that acts on the object.