A 40-kg crate is being lowered with a downward acceleration is 2.0 m/s 2 by means of a rope. (a) What is the magnitude of the force exerted by the rope on the crate?
(b) What would be the magnitude of the force exerted by the rope if the crate were being raised with an acceleration of 2.0 m/s 2?

In a system, when potential energy decreases, then entropy also decreases. true false

How many neutrons does plutonium -196 with an atomic number of 78.

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =