1) The unit of power is

Why are common measurement systems important

kenny6666 [7]

So that international people don't mistake units for others. ex 1 inch could be mistaken for 1 cm in non American countries

6 0

3 years ago

A child tugs on a rope attached to a 0.62 kg toy with a horizontal force of 16.3 N. A puppy pulls the toy in the opposite direct

sattari [20]

Answer:

$a=51.77\ m/s^2$

Explanation:

Given that,

The mass of a toy, m = 0.62 kg

Force with which a child pull the toy = 16.3 N

The force with which the toy pulled in the opposite direction = -15.8 N

We need to find the acceleration of the toy. Let F be the net force acting on the toy. It is equal to :

F = 16.3 N - (-15.8 N)

= 32.1 N

Let a be the acceleration of the toy. Using Newton' second law of motion to find it.

F = ma

$a=\dfrac{F}{m}\\\\a=\dfrac{32.1}{0.62}\\\\a=51.77\ m/s^2$

So, the acceleration of the toy is $51.77\ m/s^2$ .

5 0

3 years ago

A student hears a police siren. What would change the frequency that the student hears? check all that apply

andriy [413]

Considering the Doppler efect, the frequency heard by the student would change if:

if the student walked toward the police car.
if the student walked away from the police car.
if the police car moved toward the student.
if the police car moved away from the student.

<h3>Doppler effect</h3>

The Doppler effect is defined as the change in the apparent frequency of a wave produced by the relative motion of the source with respect to its observer. In other words, this effect is the change in the perceived frequency of any wave motion when the sender and receiver, or observer, move relative to each other.

The following expression is considered the general case of the Doppler effect:

$f'=f\frac{v+-vR}{v-+vE}$

Where:

f', f: Frequency perceived by the receiver and frequency emitted by the transmitter, respectively. Its unit of measurement in the International System (S.I.) is the hertz (Hz), which is the inverse unit of the second (1 Hz = 1 s⁻¹)
v: Wave propagation speed in the medium. It is constant and depends on the characteristics of the medium. In this case, the speed of sound in air is considered to be 343 m/s.
vR, vE: Receiver and transmitter speed respectively. Its unit of measure in the S.I. is the m/s
±, ∓:
We will use the + sign:

In the numerator if the receiver approaches the sender
In the denominator if the sender moves away from the receiver

We will use the - sign:

In the numerator if the receiver moves away from the sender
In the denominator if the sender approaches the receiver

In summary, the Doppler Effect is an alteration of the observed frequency of a sound due to the movement of the source or the observer, that is, they are changes in the frequency and wavelength of a wave due to the relative movement between the wave source and the observer.

<h3>Changes on the frequency </h3>

In this case, considering the Doppler effect, the frequency heard by the student would change if: