Question 7 (1 point)

A computer is reading data from a rotating cd-rom. at a point that is 0.0130 m from the center of the disk, the centripetal acce

likoan [24]

The formula relating acceleration and angular velocity is:

a = ω^2 r

where a is acceleration, ω is angular velocity and r is radius

But the angular velocity ω is constant all throughout the disk therefore:

a1 / r1 = a2 / r2

So at points:

r1 = 0.0130 m -> a1 = 393 m/s^2

r2 = 0.0884 m -> a2 = ?

393 / 0.0130 = a2 / 0.0884

a2 = 2,672.4 m/s^2

6 0

2 years ago

Varg sees a spring that has a spring constant of 4 N/m that is stretched 5 m. He stretches the spring an additional 5 m. Conside

AysviL [449]

Answer:

Elastic potential energy, E = 200 J

Explanation:

It is given that,

Spring constant, K = 4 N/m

initial stretching in the spring, x = 5 m

Finally, it is stretched an additional 5 m i.e. x' = 5 m

Let E is the elastic energy in the spring after Varg stretches the spring. it is given by :

$E=\dfrac{1}{2}k(x+x')^2$

$E=\dfrac{1}{2}\times 4\times (10)^2$

E = 200 J

So, the elastic energy in the spring after Varg stretches the spring is 200 J. hence, this is the required solution.

8 0

2 years ago

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For the material in the previous question that yields at 200 MPa, what is the maximum mass, in kg, that a cylindrical bar with d

Sedaia [141]

Answer:

The maximum mass the bar can support without yielding = 32408.26 kg

Explanation:

Yield stress of the material ( $\sigma$ ) = 200 M Pa

Diameter of the bar = 4.5 cm = 45 mm

We know that yield stress of the bar is given by the formula

Yield Stress = $\frac{Maximum load}{Area of the bar}$

⇒ $\sigma$ = $\frac{P_{max} }{A}$ ---------------- (1)

⇒ Area of the bar (A) = $\frac{\pi}{4}$ × $D^{2}$

⇒ A = $\frac{\pi}{4}$ × $45^{2}$

⇒ A = 1589.625 $mm^{2}$

Put all the values in equation (1) we get

⇒ $P_{max}$ = 200 × 1589.625

⇒ $P_{max}$ = 317925 N

In this bar the $P_{max}$ is equal to the weight of the bar.

⇒ $P_{max}$ = $M_{max}$ × g

Where $M_{max}$ is the maximum mass the bar can support.

⇒ $M_{max}$ = $\frac{P_{max} }{g}$

Put all the values in the above formula we get

⇒ $M_{max}$ = $\frac{317925}{9.81}$

⇒ $M_{max}$ = 32408.26 Kg

There fore the maximum mass the bar can support without yielding = 32408.26 kg

3 0

3 years ago

During the first 6 years of its operation, the Hubble Space Telescope circled the Earth 37,000 times, for a total of 1,280,000,0

madreJ [45]

Answer:

$Kilometers\ in\ 1\ Orbit=\frac{1.28*10^9 Km}{3.7*10^4orbits}$

$Kilometers\ in\ 1\ Orbit=3.46*10^4 Km/Orbit$

Explanation:

Given Data:

Numbers of times Telescope cycled around the earth in 6 years=37,000 times

Total Distance traveled in 6 years by the Hubble Space Telescope=1,280,000,000 Km

Find:

Kilometers in one Orbit=?

Solution:

Kilometers in 37,000 Orbits=1,280,000,000 Km

Kilometers in 1 Orbit=1,280,000,000/37,000

In Scientific Notation:

$Kilometers\ in\ 3.7*10^4\ Orbits=1.28*10^9 Km$

$Kilometers\ in\ 1\ Orbit=\frac{1.28*10^9 Km}{3.7*10^4 orbits}$

Kilometers in 1 Orbit=34594.594 Km

Kilometers in 1 Orbit in Scientific notation:

$Kilometers\ in\ 1\ Orbit=3.46*10^4 Km$

8 0

3 years ago

Describe the energy change in the particles of a substance during melting. A) The kinetic energy of the particles remains unchan

Rina8888 [55]

Answer:

As ice melts into water, kinetic energy is being added to the particles. This causes them to be 'excited' and they break the bonds that hold them together as a solid, resulting in a change of state: solid -> liquid.

Explanation:

As we may know, the change in state of an object is due to the change in the average kinetic energy of the particles.

This average kinetic energy is proportional to the temperature of the particles.

This is because heat is a form of energy; by adding energy to ice - heat, you "excite" the water molecules, breaking the interactions in the lattice structure and forming weaker, looser hydrogen-bonding interactions.

This causes the ice to melt. This is demonstrated in the image below.

More generally, when you remove energy - the object cools down, the particles move a lot slower. So slow, that they individually attract other molecules more than before, and this results in a physical change that also changes the state.

3 0

2 years ago

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