The bimetallic strip in a fire alarm is made of two metals with different expansion rates bonded together to form one piece of metal. Typically, the low-expansion side is made of a nickel-iron alloy called Invar, while the high-expansion side is an alloy of copper or nickel. The strip is electrically energized with a low-voltage current. When the strip is heated by fire, the high-expansion side bends the strip toward an electrical contact. When the strip touches that contact, it completes a circuit that triggers the alarm to sound. The width of the gap between the contacts determines the temperature that will set off the alarm.
Answer: The tension in the string is zero
Explanation:
Answer:
So it will lift the mass by h = 17 m
Explanation:
As per energy conservation we know that

here we know that


now we have


so work done by the engine is 250 J
now we have



It’s B I’m not sure it the right one