A boy throws a 1-kg rock with a force of 5 N. What is the acceleration of the rock when he lets go of it?

An ideal otto cycle has a compression ratio of 10.5, takes in air at 90 kpa and 40°c, and is repeated 2500 times per minute. using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kw of power. cv=0.718 kj/kg-k, cp=1.005 kj/kg-k, r=0.287 kj/kg-k, k=1.4. (61.0%; 148 kw)