Which of the following explains why parallax is used to measure stars? It takes into consideration the changing brightness of stars.
It provides greater accuracy for measuring stars near the earth.
It takes into consideration the changing position of stars.
It provides greater accuracy for measuring stars far from the earth.

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

Which of the following statement is false ? a.batteries should never be stored on metal trays or outside in the elements)b, battery acid cannot be neutralized)c.do not stack batteries on top of each other)d.never put a damaged battery in a dumpster. i

What is the gravitational attraction between a dating couple whose centers of mass are 0.630 m apart if the boy weighs 715 n and the girl weighs 465 n?