Each element has its own emission and absorption lines. What is the best explanation for this? Each element has a specific number of protons and neutrons.
Each element has a distinct number of electrons.
Each element has a unique set of physical characteristics.
Each element has unique energy levels.

What is the weight of a 8-kg substance in n, kn, kg·m/s2, kgf, lbm·ft/s2, and lbf?

Atruck going 15 kmôź°€h has a head-on collision with a small car going 30 kmôź°€h. which statement best describes the situation? (a) the truck has the greater change of momentum because it has the greater mass. (b) the car has the greater change of momentum because it has the greater speed. (c) neither the car nor the truck changes its momentum in the collision because momentum is conserved. (d) they both have the same change in magnitude of momentum because momentum is conserved. (e) none of the above is necessarily true. 2. a small boat coasts at constant speed under a bridge. a heavy sack of sand is dropped from the bridge onto the boat. the speed of the boat (a) increases. (b) decreases. (c) does not change. (d) without knowing the mass of the boat and the sand, we can’t tell.

The electricity that is delivered to our homes from regional generating stations uses high voltage to increase the safety of transmitting electricity to keep the available power the same despite the low current to induce magnetic fields in the wires to increase the magnetic field produced by the current