Question

two men tried hard and are able to push a heavy box . later wheels were fixed to the same box and a single man could move it easily . why?

Answer 1

Dear Student,

This is because rolling friction takes place. Rolling Friction is much easier than sliding friction. When both the men were pushing the box, it had no wheels thus making it an act of sliding friction. Later when wheels were added, the pushing was made easier due to the act of rolling friction.

Regards