The electroscope was a tool used in the early days of classical physics to explore the way in which charges interact, enabling measurement of small forces, and establishing coulomb's law. if there are two balls each the same mass hanging by threads of the same length and equally charged then they repel one another and push apart. gravity pulls them back toward one another. let each ball have a mass of 2 g (0.002 kg), and be hanging from a nearly weightless thread 0.15 m long. if they settle into being pushed to 3 cm part (0.03) m, answer these questions. determine the charge on each ball.
how many electrons are there on each ball?
what will happen in an identical situation if the mass of the balls is cut in half?
what would happen if the charge on each ball is doubled?

Order the sequence of ideas that lead to marie curies discovery of radioactive elements number the events in chronological order starting with the oldest

Acrow drops a 0.11kg clam onto a rocky beach from a height of 9.8m. what is the kinetic energy of the clam when it is 5.0m above the ground? what is its speed at that point?

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.