3. When performing overhead work on scaffolding, what protective measures must be taken to prevent objects
from falling and striking a person below?
a. Fall arrest systems are used.
b. Alarm systems should be enabled.
c. Toeboards, debris nets, or canopies must be applied.
d. Warning tags are posted on the scaffold.

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.