Final answer:
A heavily loaded trailer on the highway bounces less than an empty one due to the weight dampening the suspension system's oscillations. A 1.2-ton truck freely descending a 150m hill converts potential energy into kinetic energy.
Step-by-step explanation:
If you are observing a trailer on the highway and you notice that its trailer is bouncing up and down slowly, it is more likely that the trailer is heavily loaded. A trailer that is near its capacity will typically have suspension systems that are compressed due to the weight, and will not bounce as much because the heavy load dampens the oscillation of the springs.
In contrast, an empty trailer has more springiness to its suspension, allowing it to bounce more freely and with greater amplitude when it encounters bumps or uneven surfaces on the highway.
A truck of mass 1.2 tons parked at the top of a 150m high hill that lets it run freely down to the bottom experiences a conversion of potential energy to kinetic energy. The gravitational potential energy at the top of the hill is converted into kinetic energy as the truck moves down the hill, enabling it to gain speed. The total energy is conserved during the truck's descent, assuming no external forces such as friction or air resistance are acting on it.