Why is it difficult to walk on ice ?

Why is it difficult to hold a school bag having a strap made of a thin and strong string?

Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.

Sometimes it is difficult to recognize a voice over telephone,why?

Why has it been difficult to study the chemistry of radon?

Why are the symptoms of toxicity difficult to identify?

Three persons walk along a circle and require 10m, 15m and 18 m respectively to complete the circle. They start to walk along the circle from the same point and at the same time. Find after what time they meet again at the starting point for the first time.

Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

It is difficult to burn a heap of green leaves, but dry leaves catch flre easily. Explain.