Aprojectile is launched in the horizontal direction. it travels 2.050 m horizontally while it falls 0.450 m vertically, and it then strikes the floor. a. how long is the projectile in the air? b. what was the original velocity of the projectile? c. what is the velocity in the horizontal direction of the projectile when it strikes the floor? d. what is its velocity in the vertical direction at this time? e. what is the magnitude of its velocity as it strikes the floor?

A2-kg bowling ball is 2.5 meters off the ground on a post when it falls. just before it reaches the ground, it is traveling 7 m/s. assuming that there is no air resistance, which statement is true?

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?

If an electric circuit is not grounded it is best to reach out and touch it to provide the ground a.true or b.false