How safe is your design using 8-mm bolts that yield at 0.5 MPa? That is, can you quantify the extra supplied cross-sectional area as a ratio called the factor of safety? The factor of safety i

An inventor claims to have developed a reversed heat engine (ie. a heat pump) which is able to deliver 10 kj heat into the room at 20°c from outside ambient temperature of -10°c by consuming only 2 kj electricity in winter. this claim is a)-impossible b)-possible only if the heat pump is ideal c)-practically possible d)-unable to be assessed as it depends on the working fluid used in the heat pump.