5 ms·
More mass means more kinetic energy when moving. In the vast majority of cars, all the kinetic energy is wasted as heat when braking. More mass means more rolli
by nayuki 4y ago
More mass means more kinetic energy when moving. In the vast majority of cars, all the kinetic energy is wasted as heat when braking. More mass means more rolling friction on the tires. More energy wasted means more gasoline burned, more resources used, more pollution generated.
Here's another way to frame it: If weight is not waste, would you volunteer to manually pedal a 2000-kg quadricycle to drive yourself to work? Do you not appreciate the vast increase in energy to move a heavier vehicle?
Finally, look at the GMC Hummer EV versus their e-bike: https://www.gmc.com/electric/hummer-ev/insider/awd-ebike https://www.gmc.com/electric/hummer-ev/insider/awd-ebike . The car weighs 4100 kg and has a 213 kWh battery. The bike weighs 43 kg and has a 48 V × 17.5 Ah = 0.84 kWh battery. In this case, one car battery has as much capacity as 250 bike batteries. Every electric car manufactured takes away natural resources that could transport many more people on lighter vehicles.
- twblalock 4y agoObviously heavier things require more energy to move. But why is that a bad thing when we have the energy and are capable of using it without emissions? Again, who is harmed?
- throw0101a 4y agoBecause heavier vehicles cause more damage to roads, bridges, etc: * https://en.wikipedia.org/wiki/Fourth_power_law https://en.wikipedia.org/wiki/Fourth_power_law And repairing/maintaining those things more often does require natural resources and creates emissions (and waste). It also takes money, which could be used towards other things like education, healthcare, or simply lower taxes if we didn't have to fix things as much.