What forces act to pull the poles of a magnet together, or to push them apart?

A wheel with moment of inertia 25 kg. m2 and angular velocity 10 rad/s begins to speed up, with angular acceleration 15 rad/sec2

Pani-rosa [81]

Answer:

(A) Angular speed 40 rad/sec

Rotation = 50 rad

(b) 37812.5 J

Explanation:

We have given moment of inertia of the wheel $I=25kgm^2$

Initial angular velocity of the wheel $\omega _0=10rad/sec$

Angular acceleration $\alpha =15rad/sec^2$

(a) We know that $\omega =\omega _0+\alpha t$

We have given t = 2 sec

So $\omega =10+15\times 2=40rad/sec$

Now $\Theta =\omega _0t+\frac{1}{2}\alpha t^2=10\times 2+\frac{1}{2}\times 15\times 2^2=50rad$

(b) After 3 sec $\omega =10+15\times 3=55rad/sec$

We know that kinetic energy is given by $Ke=\frac{1}{2}I\omega ^2=\frac{1}{2}\times 25\times 55^2=37812.5J$

7 0

3 years ago

How do we know what is inside of Earth ?

Maslowich

Answer:

Most of what we know about the interior of the Earth comes from the study of seismic waves from earthquakes. Seismic waves from large earthquakes pass throughout the Earth. These waves contain vital information about the internal structure of the Earth.

5 0

3 years ago

A 2.30-kg cylindrical rod of length 2.00 m is suspended from a horizontal bar so it is free to swing about that end. a solid sph

Marina86 [1]

Solution:

initial sphere mvr = final sphere mvr + Iω
where I = mL²/3 = 2.3g * (2m)² / 3 = 3.07 kg·m²
0.25kg * (12.5 + 9.5)m/s * (4/5)2m = 3.07 kg·m² * ω
where: ω = 2.87 rad/s

So for the rod, initial E = KE = ½Iω² = ½ * 3.07kg·m² * (2.87rad/s)²
E = 12.64 J becomes PE = mgh, so
12.64 J = 2.3 kg * 9.8m/s² * h
h = 0.29 m

h = L(1 - cosΘ) → where here L is the distance to the CM
0.03m = 1m(1 - cosΘ) = 1m - 1m*cosΘ
Θ = arccos((1-0.29)/1) = 44.77 º

8 0

3 years ago

7. A particle is forced to move in a straight line path. It returns to the starting point after 10 s. The total distance covered

lutik1710 [3]

d. All three statements are true.

8 0

1 year ago

Which of the following processes DOES NOT occur during the convective transfer of heat within a container of air? Group of answe

vovangra [49]

The volume of a warmed part of the air is reduced and its density increases.

Explanation:

In a convective form of heat transfer, the volume of a warmed part of air is not reduced and its density does not increase.

During convection, heat causes the warm part of the air to expand and its volume increases. When volume increases, density is reduced.

Convection is a form of heat transfer that involves the actual movement of particles of the medium.
It usually occurs in fluids i.e gases and liquids.
In convection, the cold part exerts a buoyant force on the warmer air below and causes it to rise.
As the warmer part is rising the cooler part replaces it and a convective cell is formed in the process.

Learn more:

Energy transfer in the sun brainly.com/question/1140127

#learnwithBrainly

7 0

3 years ago

What forces act to pull the poles of a magnet together, or to push them apart?​

What forces act to pull the poles of a magnet together, or to push them apart?