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A student uses a pencil as a lever to launch a piece of trash into the trashcan. If the student positions a marker as the fulcrum just 2.8 cm from where she applies effort, and 7 cm from the piece of trash to the fulcrum, what is the mechanical advantage the lever gives?

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.