An electric motor rotates 60 times per second if the alternating current source is 60 Hz. How many times will an electric motor rotate in one hour if the alternating current source is changed to 50 Hz?

180,000

Explanation:

Frequency is a quantity that is measured in Hertz [Hz] and it represents the number of rotations per second.

A motor with a frequency of 50 Hz will rotate 50 times per second.

Since we don't want to know how many times it rotates per second, but per hour. The first step is to find how many seconds there are in an hour and then multiply that amount by 50.

Seconds in an hour:

there are 60 seconds per minute, and 60 minutes per hour, thus there are

60*60 = 3,600 seconds in an hour

We know that the motor will rotate 50 times per second so to find the number of rotations in 1 hour =  3,600 seconds we multiply:

50*3,600 = 180,000 rotations

probably not if net force is zero

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.