Which statement accurately describes a balanced force? A 25-N force acts on the left side of the marble at the same time as a 25-N force acts on the right side of the marble.

A 2-N force presses down on the marble at the same time as a 1.5-N force presses up on the marble.

A marble rolling downhill suddenly comes to rest at a garden wall.

A marble resting on the sidewalk suddenly begins to roll downhill without being touched.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Which of the following refers to refers to how well the control system responds to sudden changes in the system. a)-transient regulation b)- distributed regulation c)-constant regulation d)-steady-state regulation

Brief discuss how the presence of dislocations in crystal structures can be an advantage and a disadvantage to engineer and designers.