Which of the following is an accurate statement about vectors? it is possible to add a scalar quantity to a vector. if two vectors have unequal magnitudes, it is possible that their vector sum is zero. rotating a vector about an axis passing through the tip of the vector does not change the vector. the magnitude of a vector can be zero even if one of its components is not zero. the magnitude of a vector may be positive even if all of its components are negative.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

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.

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