An electric clock is hanging on a wall. as you are watching the second hand rotate, the clock's battery stops functioning, and the second hand comes to a halt over a brief period of time. which one of the following statements correctly describes the angular velocity w and angular acceleration of the second hand as it slows down?
a. w and a are both negative
b. w is positive and a is negative
c. w is negative and a is positive
d. w and a are both positive

B. W is positive and a is negative

Explanation:

As we know that the angular speed of the second clock is in positive direction so as it comes to halt from its initial direction of motion then we have

initial angular velocity is termed as positive angular velocity

now it comes to stop so angular acceleration is taken in opposite to the direction of angular speed

so we will have

so here correct answer is

B. W is positive and a is negative

gravity

explanation:

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.