#1 A block attached to a cable is descending with acceleration of 0.48 m/s . The tension in the cable is 270N . 14 pts. Determine the mass of the block. #2 A spring with the spring constant of 4500 N/m is compressed by 75.0 mm and is in touch with a 14 pts. 2.50 kg block. The spring is released and pushes the block to move. a) Determine the work done by the elastic force on the block. b) Find the speed developed by the block when the spring is completely relaxed? (Neglect friction). #3 An engine receives 3400 kJ heat from a hot reservoir and exhausts 2300 kJ of heat in each cycle. 14pts. Determine a ) the efficiency of the heat engine. b) the power delivered by the engine if the time of its cycle is 5.8 s