2. Suppose a person uses a mechanical jack to lift half the weight of a car with a mass of 1200 kg. During each stroke of the jack handle, the person's hand is pushing for a distance of 40.0 cm but the car is lifted only 5.0 mm. (a) Assuming the jack is 100% efficient, how much force must the person exert on the handle as the car is lifted? (b) If the actual amount of force required on the handle is 90.0 N, what is the actual efficiency of the jack?