A box slides north on a smooth horizontal floor while three constant forces act on it:

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A box slides 4 m4\,\text{m} north on a smooth horizontal floor while three constant forces act on it: (i) 20 N20\,\text{N} due north, (ii) 15 N15\,\text{N} due east, (iii) 50 N50\,\text{N} vertically downward. Which one of the following statements about the work done by these forces during the slide is correct? (a) Forces (i) and (ii) do positive work; force (iii) does negative work. (b) Only force (i) does positive work; forces (ii) and (iii) do zero work. (c) All three forces do positive work because each has non-zero magnitude. (d) Only force (i) does positive work; forces (ii) and (iii) do negative work.

Related theory

Browse the problem library