Which quantity is measured as electrical power?
the time rate of energy transfer
the net amount of energy transferred into a circuit
the number of charges flowing in a conductor per unit time
the amount by which a circuit element slows the flow of charge

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.