Please help me! I don't understand how to do this! Part 1: A 6 kg shopping cart goes from a velocity of 0.9 m/s to a velocity of 6 m/s over the course of 2.0 seconds. What is the cart's acceleration?

Part 2: What is the net force acting on the shopping cart during that time? You will need your answer from the previous part.

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.