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3 years ago

What is dark matter?

Physics

2 answers:

erastova [34]3 years ago

8 0

Dark matter is a hypothetical type of matter distinct from baryonic matter, neutrinos and dark energy.

Alinara [238K]3 years ago

5 0

Dark matter is a type of matter distinct from baryonic matter

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the maximum displacement of an oscillatory motion is A=0.49m. determine the position x at which the kinetic energy of the partic

kipiarov [429]

Answer:0.4 m

Explanation:

Given

Maximum displacement A=0.49

The sum of kinetic and elastic potential energy is $\frac{1}{2}kA^2$

where k=spring constant

U+K.E.= $\frac{1}{2}kA^2$

when K.E.=U/2

K.E.=kinetic energy

U=Elastic potential Energy

$\rightarrow \ U+\frac{U}{2}=\frac{1}{2}KA^2\\\rightarrow \ \frac{3U}{2}=\frac{1}{2}KA^2\\\rightarrow \ U=\frac{1}{3}KA^2\\\rightarrow \ \frac{Kx^2}{2}=\frac{1}{3}KA^2\\\\x=\sqrt{\frac{2}{3}}A\\x=0.4\ m$

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3 years ago

You are tasked with calibrating the springs for a pinball machine. Your method of testing the springs is by attaching masses ont

choli [55]

Answer:

$490.5\ \text{N/m}$

Explanation:

m = Mass attached to spring = 14 kg

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

x = Displacement of spring = $78-50=28\ \text{cm}$

k = Spring constant

The force balance of the system is given by

$kx=mg\\\Rightarrow k=\dfrac{mg}{x}\\\Rightarrow k=\dfrac{14\times 9.81}{0.28}\\\Rightarrow k=490.5\ \text{N/m}$

The spring constant for that spring is $490.5\ \text{N/m}$ .

6 0

3 years ago

What is the shape of the earth's orbit around the sun?

Daniel [21]

............D. Elliptical

7 0

3 years ago

Read 2 more answers

Which statement about moons is true?

kotegsom [21]

Answer:

Explanation:

All of the other answers don't make much sense

8 0

3 years ago

You push your couch a distance of 3.9 m across the living room floor with a horizontal force of 220.0 n. the force of friction i

Mrac [35]

The general formula to calculate the work is:

$W=Fd \cos \theta$

where F is the force, d is the displacement of the couch, and $\theta$ is the angle between the direction of the force and the displacement. Let's apply this formula to the different parts of the problem.

(a) Work done by you: in this case, the force applied is parallel to the displacement of the couch, so $\theta=0^{\circ}$ and $\cos \theta=1$ , therefore the work is just equal to the product between the horizontal force you apply to push the couch and the distance the couch has been moved:

$W=Fd=(220.0 N)(3.9 m)=858 J$

(b) work done by the frictional force: the frictional force has opposite direction to the displacement, therefore $\theta=180^{\circ}$ and $\cos \theta=-1$ . Therefore, we must include a negative sign when we calculate the work done by the frictional force:

$W=-Fd=-(144.0 N)(3.9 m)=-561.6 J$

(c) The work done by gravity is zero. In fact, gravity (which points downwards) is perpendicular to the displacement of the couch (which is horizontal), therefore $\theta=90^{\circ}$ and $\cos \theta=0$ : this means

$W=0$ .

(d) Work done by the net force:

The net force is the difference between the horizontal force applied by you and the frictional force:

$F=220 N-144 N=76 N$

And the net force is in the same direction of the displacement, so $\theta=0^{\circ}$ and $\cos \theta=1$ and the work done is

$W=Fd=(76 N)(3.9 m)=296.4 J$

4 0

3 years ago