Question

Why do gymnasts apply a coarse substance to their hands

Answer 1

WHAT KIND OF COARSE SUBSTANCES DO GYMNASTICS USE?
Gymnastics use coarse substances like chalk powder ( magnesium carbonate (MgCO3))

HOW DOES  CHALK HELP??
The chalk powder that they apply is different from the other chalk we use in our daily life.The chalk powder that they use absorbs the sweat ,and hence giving a stronger grip ,making it not slippery.
Other reason why they use coarse substances is to increase the friction and oppose the forward friction
There are two kinds of chalk substances which hey use:
1.)liquid chalk-----------------it solidifies in no time and helps for more grip
2)chalk powder------------------------absorbs sweat 



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Answer 2

gymnasts use coarse substances as they need grip. so friction is increased by adding a coarse substance.