What is the change in internal energy if 20 j of heat is released from a system and the system does 50 j of work on the surroundings?
a.-80 j
b.-20 j
c.80 j
d.20 j

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Give your knowledge of these things in your paper, you will compare and contrast analog and digital signals to determine which is more reliable for encoding and transmitting information. you’ll compare these features: signal shape numerical values for signal measurements amount of data that can be transmitted energy requirements privacy and security (ability of the signal to be encoded in a secret code) clarity of signal in the space provided, write down what you already know about any of these features. if you’re not sure, write down questions you might have about the features.

How are series and parallel circuits simililar? both have multiple paths for electrons to travel. both require resistors in their circuits. both require a switch to complete the circuit. both have at least one path for electrons to travel.