Students in a science class want to design an investigation to determine if fertilizer added to soil affects the average height of a plant over time. Which items would the students need to complete this investigation?
A tape measure, graph paper, a plant, and soil samples with the same amount of fertilizer
A microscope, a beaker, a plant, and soil samples with the same amount of fertilizer
A computer, a stopwatch, a plant, and soil samples with different amounts of fertilizer
A ruler, a calculator, a plant, and soil samples with different amounts of fertilizer

Ascientist is tracking an object orbiting the sun that is found between mars and jupiter. in order to classify the object as an asteroid, it must be at least

The energy of a photon was found to be 3.38 × 10–19 j. planck’s constant is 6.63 × 10–34 j • s. which color of light corresponds to this photon?

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?