It says that the force of a spring is always opposite to the direction in which you stretch it or compress it. (the direction of 'x')
In other words, a spring that's disturbed always tries to put itself back to it's normal length, where x would be zero.
The speed of Nancy who ran a distance of 5 km in 30 minutes is 10000 meters(m) per hour(h).
<h3>What is the rate of speed?</h3>
The rate of speed is the rate at which the total distance is travelled in the time taken. Rate of speed can be given as,

Here, (d) is the distance travelled by the object and (t) is the time taken but the object to cover that distance.
Nancy ran a distance of 5 km in 30 minutes. There are 60 minutes in one hour. Thus, the time in hour for which Nancy ran is,
The meters in 5 kilometers is,

She ran 5000 kilometers in 0.5 hours. Thus, the speed of her is,

Thus, the speed of Nancy who ran a distance of 5 km in 30 minutes is 10000 meters(m) per hour(h).
Learn more about the rate of speed here:
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Hello! Please answer my question that I just posted I really need answers. I don’t know sorry hope u fine someone that does know
The correct choice is
D. 22 Hz and 42 Hz.
In fact, the beat frequency is given by the difference between the frequencies of the two waves:

In this problem, the beat frequency is
, therefore the only pair of frequencies that gives a difference equal to 20 Hz is
D. 22 Hz and 42 Hz.
Those two units can be compared to a 'mile per hour' and a 'mile per hour - hour'.
One is a rate. The other is a quantity, after maintaining a rate for some time.
-- 'Joule' is a unit of energy. It's the amount of work (energy) you do
when you push with a force of 1 newton though a distance of 1 meter.
Lifting 10 pound of beans 3 feet off the floor takes about 40.7 joules of energy.
-- 'Watt' is a <u><em>rate</em></u> of using energy . . . 1 joule per second.
If you lift 10 pounds 3 feet off the floor in 1 second, your <em>power</em> is 40.7 watts.
-- 'Watt-second' is the amount of energy used in one second,
at the rate of 1 joule per second . . . 1 joule.
-- 'Watt-hour' is the amount of energy used in one hour,
at the rate of 1 joule per second . . . 3,600 joules.
-- 'Kilowatt' is a bigger <em>rate</em> of using energy . . . 1,000 joules per second.
-- 'Kilowatt - second' is the amount of energy used in one second,
at the rate of 1,000 joules per second . . . 1,000 joules .
-- 'Kilowatt - hour' is the amount of energy used in one hour,
at the rate of 1,000 joules per second . . . 3,600,000 joules .
Depending on where you live, 3,600,000 joules of energy bought
from the electric company costs something between 5¢ and 25¢.