8. which phrase best describes an atom? (a) a positive nucleus surrounded by a ha dnegative shell(b) a positive nucleus surrounded by a cl udof negative charges(c) a hard sphere with positive particlesuniformly embedded(d) a hard sphere with negative particlesuniformly embedded

The best answer is B The nucleus is after all positively charged and the shells are a cloud of negatively charged particles that surround the nucleus.

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy