Question

You have two suitcases. First suitcase is of 5 N weight and with rollers and second suitcase is of 2 N but without rollers. Now you are pulling two suitcases. Which one has less friction?

• A.
  1st suitcase has less friction
• B.
  2nd suitcase has less friction
• C.
  Both the suitcases have the same friction
• D. The frictional force of the suitcases cannot be compared

Answer 1

The correct option is D The frictional force of the suitcases cannot be compared

We know as weight (here it is equal to normal force) increases then frictional force increases.
Weight of 1st suitcase > Weight of 2nd suitcase
So, frictional force on 1st suitcase should be greater than the 2nd suitcase by virtue of its weight
Also we know that rolling friction is lesser than the sliding friction. 1st suitcase has rollers so it will have rolling friction and 2nd suitcase does not have rollers so it will have sliding friction.
Thus, frictional force on 1st suitcase should be lesser than the 2nd suitcase due to rollers.
Hence, without measuring the frictional forces we cannot say which suitcase has the lower friction.