A car engine exerts a steady forward thrust of 3.0kN to move the car 0.40km in a straight line.
(i) Calculate the work done by the engine, expressing your answer in kilojoules.
(ii) If brakes apply the same magnitude of force opposite to the displacement over the same distance, calculate the work done by the braking force and state its sign.
a. (i) Work done by the engine in kJ
b. (ii) Work done by the braking force with sign