!!!HELP ASAP!!!<br>in witch situation is work being done?<br>theres a photo added.

Please help me with this question guys.

katen-ka-za [31]

Answer:

<em>The average speed is 22.2 km/h</em>

Explanation:

<u>Average Speed</u>

Given an object travels a total distance d and took a total time t, then the average speed is:

$\displaystyle \bar v=\frac{d}{t}$

The mailman first drives d1=7 km at v1=15 km/h. The time taken to drive is:

$\displaystyle t1=\frac{d1}{v1}=\frac{7}{15}=0.467\ h$

Then he drives d2=7 km at v2=43 km/h taking a time of:

$\displaystyle t2=\frac{d2}{v2}=\frac{7}{43}=0.163\ h$

The total time is

t=0.467 h + 0.163 h = 0.63 h

The total distance is

d = 7 km + 7 km = 14 km

The average speed is:

$\displaystyle \bar v=\frac{14}{0.63}=22.2\ km/h$

The average speed is 22.2 km/h

7 0

2 years ago

DESCRIBE THE FORMATION OF THE SOLAR SYSTEM ACCORDING TO THE NEBULAR THEORY

marishachu [46]

When a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star.This explosion made waves in space which squeezed the cloud of gas & dust.

8 0

2 years ago

A cell phone uses a 3. 0 V battery. The circuit board it uses needs a 0. 05 A current. What size resistor is needed to generate

Marta_Voda [28]

The value of resistance will be 60 ohms. Resistance is the opposition force offered to the flow of electric current. The ratio of the voltage to the electric current passing through the wire.

<h3>What is a resistor?</h3>

A resistor is a two-terminal passive electrical component that acts as a circuit element by implementing electrical resistance.

Resistors are used to limit current flow, alter signal levels, divide voltages, bias active devices, and complete transmission lines in electronic circuits.

The given data in the problem is;

V is the voltage = 3. 0 V

I is value of electric current= 0. 05 A

R is the resistance=?

According to ohm's law, the potential difference between the two ends of the conductor is equal to the product of electric current and the resistance generated.

So from the ohm law;

V= IR

$\rm R = \frac{V}{I} \\\\ \rm R = \frac{3}{0.05} \\\\ \rm R =60 \ ohm$

Hence the value of resistance will be 60 ohms.

To learn more about the resistor refer to the link;

brainly.com/question/1322424

3 0

2 years ago

A physics major is working to pay her college tuition by performing in a traveling carnival. She rides a motorcycle inside a hol

il63 [147K]

Answer:

v = 12.1 m/s

Explanation:

When at the top of the circle, there are two forces acting on the combined mass of the rider and the motorcycle.
These are the force of gravity (downward) and the normal force, which is directed from the surface away from it, perpendicular to the surface.
In this case, as the motorcycle runs in the interior of the circle, at the top point this force is completely vertical, and is also downward.
Since the motorcycle is moving in a vertical circle, there must be a force, keeping the object moving around a circle.
This force is the centripetal force, aims towards the center of the circle, and is just the net force aiming in this direction at any point.
At the top point, this force is just the sum of the normal force and the weight of the mass of the rider and the motorcycle combined, as follows (we take the direction towards the center as positive):

$F_{c} = N + m*g (1)$

Now, we know that the centripetal force is related with the tangential speed at this point and the radius of the circle as follows:

$F_{c} = m*\frac{v^{2}}{r} (2)$

Since the normal force takes any value as needed to make (1) equal to (2), if the speed diminishes, it will be needed less force to keep the equality valid.
In the limit, when the motorcyvle tires barely touch the surface, this normal force becomes zero.
In this condition, from (1) and (2), we can find the minimum possible value of the speed that still keeps the motorcycle touching the surface, as follows:
$v_{min} =\sqrt{r*g} =\sqrt{15.0m*9.8m/s2} = 12.1 m/s (3)$

6 0

3 years ago

A microphone is attached to a spring that is suspended from the ceiling, as the drawing indicates. Directly below on the floor i

svet-max [94.6K]

Answer:

$0.261\ \text{m}$

Explanation:

$\Delta f$ = Change in frequency = 2.1 Hz

$f$ = Frequency of source of sound = 440 Hz

$v_m$ = Maximum of the microphone

$v$ = Speed of sound = 343 m/s

$T$ = Time period = 2 s

We have the relation

$\Delta f=2f\dfrac{v_m}{v}\\\Rightarrow v_m=\dfrac{\Delta fv}{2f}\\\Rightarrow v_m=\dfrac{2.1\times 343}{2\times 440}\\\Rightarrow v_m=0.8185\ \text{m/s}$

Amplitude is given by

$A=\dfrac{v_m T}{2\pi}\\\Rightarrow A=\dfrac{0.8185\times 2}{2\pi}\\\Rightarrow A=0.261\ \text{m}$

The amplitude of the simple harmonic motion is $0.261\ \text{m}$ .

4 0

2 years ago

!!!HELP ASAP!!!in witch situation is work being done?theres a photo added.​

!!!HELP ASAP!!!in witch situation is work being done?theres a photo added.