A small rock bounces off the windshield of a moving car and experiences a large change in velocity. How does the car’s momentum change?(1 point) It has a change in momentum equal to that of the rock, in the opposite direction.

It has a much smaller change in momentum than that of the rock, in the opposite direction.
It has a much smaller change in momentum than that of the rock, in the opposite direction.

It has a change in momentum greater than that of the rock, in the opposite direction.

It does not change.

Which of Newton’s laws of motion states that an object at rest stays at rest and an object in motion stays in motion with the same speed and the same direction unless acted upon by an unbalanced force?(1 point)

Newton’s third law of motion

Newton’s second law of motion

Newton’s fourth law of motion

Newton’s first law of motion

Which is always true in a closed system?(1 point)

Velocity is constant.

Acceleration is not constant.

Momentum is conserved.

Mass is not conserved.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.