when playing curling when you rub the ice does it make it slow down or speed up ?

 

In Curling, sweeping makes the rock travel farther and straighter. Sweeping cannot make a rock move faster, only farther.


The sweeping gesture briefly polishes the ice just before the rock travels over it. Warming the ice slightly increases the total frictional melting and lets the rock to continue moving. This results in the rock moving farther.
This is technically described as "decreasing the rate of deceleration." The total reduction in friction has another outcome: Since the rock is biting less on both sides, the rock will travel straighter.