Powered and rotating type concrete troweling machines that are manually guided shall be equipped with a control switch that will automatically shut off power whenever hands of the operator are removed from equipment handles.
true or false?

True

Explanation:

Hand-held concrete troweling machines must be fitted with a control switch that automatically shuts off power when the hands of the user are separated from the handles.

One of the more important of this machine should be closed automatically because the source of energy is limited and doing this wastage of energy can be reduced.Another thing that this is also used from safety purposes.

Therefore the answer is True.

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.

this is poiselle's equation from fluid mechanic in physics. mech eng