22. Cindy created a solenoid by coiling a copper wire and attaching it to a battery. process has generated a magnetic field around the solenoid. Which of the following could Cindy
do to increase the magnetic field?
2. decrease the number of coils in the wire
b. increase the number of coils in the wire
c. decrease the voltage of the battery
dadd a plastic core to the solenoid
23. What is an electric motor?
a machine that converts energy from electricity into mechanical energy
b. a machine that converts energy from mechanical energy into electricity
c. a machine that converts energy from chemical energy into mechanical energy
d. uses combustion to create mechanical energy
_24. What is a generator?
a.
a machine that converts energy from electricity into mechanical energy
b. a machine that converts energy from mechanical energy into electricity
a machine that converts energy from chemical energy into mechanical energy
d. uses combustion to create mechanical energy
C.
I need help with all three

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

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?

Carbon-14 is a radioactive element that undergoes beta decay. which force is responsible for allowing carbon-14 to become stable? electromagnetic gravitational weak nuclear strong nuclear