Consider two bicycle riders, a and b. the two riders have equal masses mrider a = mrider b and their respective bicycles also have similar frames, mframe a = mframe b . finally, the wheels of the two bicycles have equal masses mwheel a = mwheel b and equal radii r wheel a = r wheel b but different mass distributions: the wheels of bike a have most of their masses at the rims, wheel a, while the wheels of bike b have their masses ‘spread’ evenly over the whole wheel area, wheel b. the two cyclists travel at the same speed on level ground. they approach a low hill and decide to coast up instead of hard pedalling. at the top of the hill, which of the two bikes will have a larger speed? assume no friction nor air resistance, and all the wheels roll on the ground without slipping.

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.