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2 years ago

Which statement about the positive and negative value of speed compared to velocity is true?

Physics

1 answer:

mestny [16]2 years ago

3 0

D is the answer
Velocity maybe negative or positive
while speed is always positive

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A plane flying against the wind covers the 900-kilometer distance between two aerodromes in 2 hours. The same plane flying with

Mashcka [7]

Answer:

The speed of the wind is 25 km/hr.

Explanation:

Let us call $v_p$ the speed of the plane and $v_w$ the speed of the wind. When the plane is flying against the wind, it covers the distance of 900-km in 2 hours (120 minutes); therefore;

(1). $v_p - v_w = \dfrac{900km}{120min}$

And when the plane is flying with the wind, it covers the same distance in 1 hour 48 minutes (108 minutes)

(2). $v_p+v_w= \dfrac{900km}{108min}$

From equation (1) we solve for $v_p$ and get:

$v_p = \dfrac{900km}{120min}+v_w$ ,

and by putting this into equation (2) we get:

$\dfrac{900km}{120min}+v_w+v_w= \dfrac{900km}{108min}$

$2v_w= \dfrac{900km}{108min}-\dfrac{900km}{120min}$

$2v_w = 8.3km/min - 7.5km/min$

$2v_w = 0.83km/min$

$v_w = 0.4165km/min$

or in km/hr this is

$\boxed{v_w= 25km/hr }$

4 0

2 years ago

What is the net work doneon the object over the distance shown?

GuDViN [60]

$A)F_0d$

Explanation

If you graph the force on an object as a function of the position of that object, then the area under the curve will equal the work done on that object, so we need to find the area under the function to find the work

Step 1

find the area under the function.

Area:

$\text{Area}=rec\tan gle_{green}+triangle_{gren}-triangle_{red}$ $\begin{gathered} \text{the area of a rectangle is given by} \\ A_{rec}=lenght\cdot widht \\ \text{and} \\ \text{the area of a triangle is given by:} \\ A_{tr}=\frac{base\cdot height}{2} \end{gathered}$

$\begin{gathered} \text{Area}=rec\tan gle_{green}+triangle_{gren}-triangle_{red} \\ \text{replace} \\ \text{Area}=(F_0\cdot d)+\frac{(F_0\cdot d)}{2}-\frac{(F_0\cdot d)}{2} \\ \text{Area}=(F_0\cdot d) \\ Area=F_0d \end{gathered}$

therefore, the answer is

$A)F_0d$

I hope this helps you