suppose you are on a cart, initially at rest, which rides on a frictionless horizontal track. if you throw a ball off the cart towards the left, will the cart be put into motion?

The answer is frictional force

The chemical reactions lab we did is typically called a "copper plating lab,  because the acid solution cleaned the pennies and made the copper look shinier;   the acid solution cleaned the paperclips and made them look like pennies;   &   the copper from the pennies was removed, and then added to the paperclips. 

They like garbage and they hunt during the night.