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In what direction does an applied force move an object

What is the efficiency of an engine that does 80 j of work and exhausts 320 j of heat while taking in 400 j of heat ? a. 10% b. 20% c. 80% d. 25%

Vi. on another planet, a spring with constant 4.7 n/m is set up and allowed to expand verticaly freely. 8.4kg mass is placed on the spring and the spring extends 5.28m. calculate the exected extension on earth.