Two spheres, a and b, are simultaneously projected horizontally from the top of a tower. sphere a has a horizontal speed of 40.0 meters per second and sphere b has a horizontal speed of 20.0 meters per second. which statement best describes the time required for the spheres to reach the ground and the horizontal distance they travel? [neglect friction and assume the ground is level.]

sphere a hits the ground before sphere b, and sphere a lands twice as far as sphere b from the base of the tower.
both spheres hit the ground at the same time and at the same distance from the base of the tower.
both spheres hit the ground at the same time, but sphere a lands twice as far as sphere b from the base of the tower.
both spheres hit the ground at the same time, but sphere b lands twice as far as sphere a from the base of the tower.

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?

Aball horizontally thrown from a cliff at 8m/s

Which is an advantage of subdividing science into different areas?