Ijust need someone to check my answer!

If the ama of the inclined plane below is 2, calculate the ima and efficiency. ima = efficiency =

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.

During the past 150 years in the united states, how did energy consumption compare to population growth