Do this with the roller costar in class and the 25 mm (0.067 kg) ball in projectile launcher with spring constant (k) of 200 N/m A ball of 0.067 kg is pushed against a spring of spring constant k = 200. N/m compressing the spring 0.055 m. What will be the speed of the ball as it is projected out of the launcher?

No because scientist are still changing there mines today so they are not correct to this day

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. 

The answer is d, you can easily test a theory! hope i you : )