When a block slides over a rough horizontal surface and eventually comes to rest
PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
When a block slides over a rough horizontal surface and eventually comes to rest, the work done by friction is said to be negative.
(i) State the relation between the direction of kinetic friction and the direction of displacement of the block.
(ii) Using the definition of work, explain why the work done by friction carries a negative sign.
(iii) What happens to the kinetic energy lost by the block? Describe the form into which this energy is converted.