Which of these is the best explaination for why two negatively charged balloons move apart without ever touching?
a)electrons from the one balloon jump to the other and push it, without ever touching it.
b) charged objects send little lightning bolts of electrons across the space between two balloons.
c) the space between objects is actually filled with charged particles that all interact.
d) electric charges have electric fields surrounding them to allow them to exert forces on other objects without touching them.

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Use the right-hand rule for magnetic force to determine the charge on the moving particle. this is a charge.

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.