Dynamics Challenge #2 — Newton's Second Law

Net force
on a sled.

Dynamics Easy

Problem

A 12 kg sled is pulled across the snow with a horizontal force of 30 N, while friction opposes the motion with 6 N. Calculate the net force on the sled.

Mass\( m = 12\ \mathrm{kg} \)
Pulling force\( F = 30\ \mathrm{N} \)
Friction\( f = 6\ \mathrm{N} \)
Answer innewtons

Forces along one line: signs do the geometry for you.

Hint: friction acts against the pull. The net force is what’s left of the 30 N once friction has taken its share.

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Net forceon a sled.

Problem