A block is pulled along a horizontal floor to the right by a force

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

Problem

5\,\text{kg}

block is pulled

10\,\text{m}

along a horizontal floor to the right by a

60\,\text{N}

force, while a

40\,\text{N}

force acts simultaneously to the left. The coefficient of kinetic friction between the block and floor is

0.10

. Which option correctly lists the work done (in joules) by the

60\,\text{N}

force (

W_{60}

), by the

40\,\text{N}

force (

W_{40}

), and the corresponding change in kinetic energy of the block (

\Delta K

)? (a)

W_{60}=600,\; W_{40}=-400,\; \Delta K = 100\,\text{J}

(b)

W_{60}=600,\; W_{40}=-400,\; \Delta K = 150\,\text{J}

(c)

W_{60}=600,\; W_{40}=-400,\; \Delta K = 151\,\text{J}

(d)

W_{60}=600,\; W_{40}=-400,\; \Delta K = 200\,\text{J}