A squirrel drops an acorn onto the head of an unsuspecting dog. The acorn falls 4.0 meters before it lands on the dog. We can ignore air resistance. How many seconds did the acorn fall?

The metal wire in an incandescent lightbulb glows when the light is switched on and stops glowing when it is switched off. this simple process iswhich kind of a change? a. a physical changeb. a chemical changec. a nuclear changed. an ionic change

Why do electron microscopes have higher resolving power than light microscopes?

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system