A roller coaster starts at a point 30 m above the bottom of a dip with a speed of 25 m/s. Neglect friction, what will be the speed of the rollercoaster at the top of the next slope, which is 45 m above the bottom of the dip

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. 

Newton's first law describes something special that results from the sum of all the external forces (including gravity) on an object.