Complete question is:
It's is difficult to walk on a wet floor than a smooth floor. Why?
Answer:
Because friction on wet floor is far lesser than on a smooth floor
Explanation:
On wet surfaces, the friction is far lesser than on smooth surfaces and thus the grip between the bottom of your shoes/feet and the ground is very very small and as such walking on the wet surface becomes more difficult. Whereas on Smooth surfaces, there is plenty of friction and as a result, there is enough grip between the bottom of your shoes/feet and the ground thereby making walking far easier.
