Which word describes a system in which energy moves freely in and out, but no matter enters or leaves?

An input force of 7 n is applied to a machine with a mechanical advantage of 1.75. what is the maximum the machine could lift? 12.25 n7n7.25 n26.2 n

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.

The radius of a sphere is increasing at a rate of 9 cm/ sec. find the radius of the sphere when the volume and the radius of the sphere are increasing at the same numerical rate.