Aroad engineer designs exit ramp of the ac expressway with a banked curve to allow a car to travel on the ramp with a speed of 40 mph when the ramp is ice covered and the coefficient of friction is zero. the curve has a radius of 35.0 meters.
a.) at what angle is the curve banked?
b.) if the coefficient of friction is normally 0.2, what is the maximum speed a car can negotiate the curve?
c.) if the coefficient of friction is normally 0.2, what is the minimum speed a car can negotiate the curve?

4.at 0 ºc, some amount of energy is required to change 1 kg of water from a solid into a liquid. if you had a 2 kg piece of ice, what effect would this have on the amount of thermal energy required to change the water from a solid to a liquid? it would require more energy to change solid water into liquid water because there are more molecules in this larger piece of ice. it would still require the same amount of energy to change solid water into liquid water because the entire piece of ice would still gain the same amount of energy in each case. it would require energy to be removed from the 2 kg piece of ice. the larger piece of ice already has more total energy than the smaller piece of ice, so energy must be removed for the ice to become liquid. it would require less energy to change solid water into liquid water because the energy would spread through the ice more quickly and the ice already has a larger total amount of energy because it is larger than a 1 kg piece of ice.