nazli father buys a bar fridge with a mass of 30kg. he unloads the box containing the bar fridge in his driveway and starts to push it towards the house. at first he has to push with a force of 135N to get the box to start moving. once it is moving, he has to exert a Force of 120N to keep it moving with a constant speed. for the box on the driveway, calculate the maximum coefficient of static friction?​ calculate the coefficient of kinetic friction