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3 years ago

Explain how it is possible for the smallest white dwarfs to be the most massive.

1 answer:

8 0

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.. The most massive stars, with eight times the mass of the sun or more, will never become white dwarfs<span>. Instead, at the end of their lives, they will explode in a violent supernova, leaving behind a neutron star or </span>black hole.

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Convert 9.75 millimeters to centimeters.

Alex777 [14]

0.975 is correct, to get the answer you divide the length value by 10.

4 0

3 years ago

Read 2 more answers

The angle of reflection is the angle between the normal line and the___?

Aleks [24]

Answer:

Reflected line

Explanation:

The angle between the reflected ray and the normal ray is called angle of reflection.

4 0

3 years ago

A+20 N force acts on a car and at the same time, a -30 N force acts on the

katovenus [111]

Answer:

-10 N, not balanced

Explanation:

Force is a vector quantity, so in order to find the net force on an object, we must use vector addition rule.

This means that if two forces acting on an object along the same line, we have to choose one direction as positive, and write the two forces with the correct sign.

In this problem, we have two forces acting along a line on the car:

- A first force of

$F_1 = +20 N$

- A second force of

$F_2=-30 N$

Therefore, the net force on the car is:

$\sum F=F_1+F_2=+20 +(-30)=-10 N$

Moreover, the net force on an object is said to be "balanced" if it is zero: in this case, it is not zero, so it is not balanced.

5 0

3 years ago

The work of energy theorem states that an increase in net work results in what?

Veseljchak [2.6K]

It results change only in it's kinetic energy, it's KE will increase in accord with the work-energy theorem

3 0

3 years ago

In a flying ski jump, the skier acquires a speed of 110 km/h by racing down a steep hill and then lifts off into the air from a

matrenka [14]

Answer:

Approximately $\displaystyle\rm \left[ \begin{array}{c}\rm191\; m\\\rm-191\; m\end{array}\right]$ .

Explanation:

Consider this $45^{\circ}$ slope and the trajectory of the skier in a cartesian plane. Since the problem is asking for the displacement vector relative to the point of "lift off", let that particular point be the origin $(0, 0)$ .

Assume that the skier is running in the positive x-direction. The line that represents the slope shall point downwards at $45^{\circ}$ to the x-axis. Since this slope is connected to the ramp, it should also go through the origin. Based on these conditions, this line should be represented as $y = -x$ .

Convert the initial speed of this diver to SI units:

$\displaystyle v = \rm 110\; km\cdot h^{-1} = 110 \times \frac{1}{3.6} = 30.556\; m\cdot s^{-1}$ .

The question assumes that the skier is in a free-fall motion. In other words, the skier travels with a constant horizontal velocity and accelerates downwards at $g$ ( $g \approx \rm -9.81\; m\cdot s^{-2}$ near the surface of the earth.) At $t$ seconds after the skier goes beyond the edge of the ramp, the position of the skier will be:

$x$ -coordinate: $30.556t$ meters (constant velocity;)
$y$ -coordinate: $\displaystyle -\frac{1}{2}g\cdot t^{2} = -\frac{9.81}{2}\cdot t^{2}$ meters (constant acceleration with an initial vertical velocity of zero.)

To eliminate $t$ from this expression, solve the equation between $t$ and $x$ for $t$ . That is: express $t$ as a function of $x$ .

$x = 30.556\;t\implies \displaystyle t = \frac{x}{30.556}$ .

Replace the $t$ in the equation of $y$ with this expression:

$\begin{aligned} y = &-\frac{9.81}{2}\cdot t^{2}\\ &= -\frac{9.81}{2} \cdot \left(\frac{x}{30.556}\right)^{2}\\&= -0.0052535\;x^{2}\end{aligned}$ .

Plot the two functions:

$y = -x$ ,
$\displaystyle y= -0.0052535\;x^{2}$ ,

and look for their intersection. Refer to the diagram attached.

Alternatively, equate the two expressions of $y$ (right-hand side of the equation, the part where $y$ is expressed as a function of $x$ .)

$-0.0052535\;x^{2} = -x$ ,

$\implies x = 190.35$ .

The value of $y$ can be found by evaluating either equation at this particular $x$ -value: $x = 190.35$ .

$y = -190.35$ .

The position vector of a point $(x, y)$ on a cartesian plane is $\displaystyle \left[\begin{array}{l}x \\ y\end{array}\right]$ . The coordinates of this skier is approximately $(190.35, -190.35)$ . The position vector of this skier will be $\displaystyle\rm \left[ \begin{array}{c}\rm191\\\rm-191\end{array}\right]$ . Keep in mind that both numbers in this vectors are in meters.

4 0

3 years ago