Why might a scientist use a physical model of a plant cell instead of studying a cell directly?
OA. A model can be used for things that are too simple to study
O B. A model can be used for things that are too hot to handle easily.
O C. A model can be used for things that are too large to study directly.
OD. A model can be used for things that are too small to see clearly.
directly.

What do you think car designers do if the damage caused by a crash test is too severe?

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)

Aproton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?