3. A car does an emergency stop from 144 km\h in 4s What was its deceleration?

Physics Help Please!!! All multiple choice!

1) True.
Uniform circular motion means that the angular velocity $\omega$ is constant, and since the centripetal acceleration is given by
$a=\omega ^2 r$
if $\omega$ is constant, then a is constant.

2) The correct answer is
a.) the angular velocity and linear velocities are the same
The three knots are in fact on a circle, therefore the angular velocities are the same (because they cover the same angle in the same time) and the linear velocities are the same as well, because it is given by
 $v=r \omega$
and since both r(distance from the center) and $\omega$ are the same, v is also the same.

3) b.) toward the center
In fact, an object can move on a circular path only if there is a force pushing towards the center. This force is called "centripetal force".

3 0

3 years ago

What units are used to measure force

Nastasia [14]

N, or Neutons are a common way to measure force

5 0

4 years ago

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In the final stages of production, a pharmaceutical is sterilized by heating it from 25 to 75C as it moves at 0.2 m/s through a

steposvetlana [31]

Answer:

The answer is " $12682.267\ \ \frac{W}{m^2}$ "

Explanation:

Calculating the mass flow rate of fluid:

$m= \rho AV$

$= \rho \frac{\pi}{4} D^2\ V\\\\= 100 \times \frac{\pi}{4} \times (0.0127)^2\times 0.2\\\\=0.0253 \ \frac{kg}{s}\\\\$

Calculating the amount of heat transfer.

$q =m\timesC_p(T_{m,0}-T_{m,i})$

$=0.0253 \times 4000 (75-25)\\\\=0.0253 \times 4000(50)\\\\=0.0253 \times 200,000 \\\\= 5060 \ W$

Calculating the required value for heat flux:

$q"=\frac{q}{A_s}$

$=\frac{q}{\pi DL}\\\\= \frac{5060}{\pi \times 0.0127 \times 10}\\\\= 12682.267 \frac{W}{m^2}\\$

3 0

3 years ago

"a horn emits a frequency of 1000 HZ. A 14 m/s wind is blowing toward a listener. What is the frequency of the sound heard by th

Semenov [28]

Answer:

$f_L = 1000 Hz$

Explanation:

given,

speed of wind, = 14 m/s

frequency of horn,f_s = 1000 Hz

speed of sound,V = 344 m/s

frequency heard by the listener

using Doppler effect

$f_L = \dfrac{v+v_L}{v+v_s}f_s$

f_L is the frequency of the sound heard by the listener

f_s is the frequency of sound emitted by the listener

V is the speed of sound

v_L is the speed of listener

v_s is the speed of source

now,

considering the frame of reference in which wind is at rest now, both listener and the source will be moving at 14 m/s

$f_L = \dfrac{v+14}{v+14}\times 1000$

now on solving we will get

$f_L = 1000 Hz$

hence, the frequency heard by the listener is equal to 1000 Hz

7 0

3 years ago

Which of the following is a declarative sentence

arsen [322]

Any multiple choice? I cant answer without possible answers.
But for insight a declarative sentence is a statement. For example: "I am going to the store." And Declarative sentences end with a period. (.)
Hope this helps. Just dont get confused with sentences that end in periods (.) but are really commands.

8 0

3 years ago

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