Final answer:
The question pertains to physics, dealing with hill-start techniques to prevent rolling backwards, by managing potential and kinetic energy and friction. The equation in the question determines work done, with v₁ representing speed at the hill's top and v₂ at the bottom.
Step-by-step explanation:
The student's question involves starting on a hill without rolling backwards, which refers to the physics concept of managing potential and kinetic energy, as well as friction. In the equation W = 1/m(v² − v₁²), v₁ and v₂ represent the initial and final velocities of a system, respectively. To not roll backwards on a hill, two common methods are utilized: the handbrake method and the heel-toe technique. For vehicles with an automatic transmission, the ‘hill-start assist’ feature may also be available.
In the context of the information given, v₁ stands for the speed at the top of the hill, and v₂ is the speed at the bottom. Understanding these concepts is crucial when discussing mechanisms of starting on a hill without moving back, as it involves controlling the transition between potential energy at the top of the hill and kinetic energy at the bottom, while also managing frictional forces.
Friction is not always negligible, as shown in the scenario where a car coasts down a hill, runs out of gas, and coasts further before coming to a stop at a gas station. In this event, potential energy is converted to kinetic energy and is eventually dissipated due to friction. Similarly, the weight and height of a vehicle, such as the mentioned 1,2 tons truck at the height of 150 m, significantly influence how much potential energy is available to be converted into motion.