A gas has a volume of 15 L, a temperature of 300 K, and an unknown initial pressure.
Then, the gas expands to 30 L, remains at
300 K, and has a pressure of 300 kPa. What
was the initial pressure of the gas?

With i really need the correct answer!

An electric current is flowing through the cord below.what will happen to this current if a magnet is brought near the cord? a. the electric current will stop flowing. b. it will exert a force on the voltage. c. the resistance of the wire will decrease. d. it will exert a force on the electric current.

Iwill give 30 points to whoever answers ! what is the formula for actual mechanical advantage and ideal mechanical advantage?