Given that,
Mass of each washer = 4.9 g
We need to calculate the mass of two washers in kg
Using conversion of unit
Mass of each washer

So, Mass of two washers is

Put the value of m


If 4 washer are attached to the spring
We need to calculate the applied force on the car
Using formula of force

Put the value into the formula


Hence, (i), The mass of two washers is 0.0098 kg.
(ii). The applied force on the car is 0.192 N.