Answer:
Einstein extended the rules of Newton for high speeds. For applications of mechanics at low speeds, Newtonian ideas are almost equal to reality. That is the reason we use Newtonian mechanics in practice at low speeds.
Explanation:
<em>But on a conceptual level, Einstein did prove Newtonian ideas quite wrong in some cases, e.g. the relativity of simultaneity. But again, in calculations, Newtonian ideas give pretty close to correct answer in low-speed regimes. So, the numerical validity of Newtonian laws in those regimes is something that no one can ever prove completely wrong - because they have been proven correct experimentally to a good approximation.</em>
Answer:
True
Explanation:
In this particular case, the area of the graph represents the impulse.
In fact, impulse is defined as the change in momentum of an object:

Moreover, impulse is also defined as the product between the magnitude of the force acting on an object and the duration of the collision:

If we plot a graph of the force versus the time, if the force is constant then this graph will have a rectangular shape, and the area under the graph will simply be the product

which corresponds to the definition of impulse.