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3 years ago

What is the mass moment of inertia of a 20kg sphere with a radius of 0.2m about a point on the sphere's perimeter

Physics

1 answer:

Kobotan [32]3 years ago

7 0

Answer:

I = M R^2 is the moment of inertia about a point that is a distance R from the center of mass (uniform distributed mass).

The moment of inertia about the center of a sphere is 2 / 5 M R^2.

By the parallel axis theorem the moment of inertia about a point on the rim of the sphere is I = 2/5 M R^2 + M R^2 = 7/5 M R^2

I = 7/5 * 20 kg * .2^2 m = 1.12 kg m^2

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The position of a particle moving on x-axis is given by x(t)=t^2 + 2, it’s average velocity in the final interval from t=1 to t=

san4es73 [151]

Answer:

The average velocity is 2 m/s.

Explanation:

The velocity of the particle is the time derivative of its position $x(t):$

$v =\frac{dx(t)}{dt} = \frac{d}{dt}[t^2+2]$

$v =2t$

Now the average from $t=1$ and $t=2$ is

$v_{avg} = \dfrac{v(2)-v(1)}{2-1} = \dfrac{2(2)-2(1)}{1}$

$\boxed{v_{avg} = 2 m/s} \text{ ( If the units are m/s)}$

Thus, the average velocity is 2 m/s.

8 0

4 years ago

A person is listening with his ear against the rail for an oncoming train. When the train is 1.65 km away, how long will it take

Vitek1552 [10]

Answer:

Time = 0.317 seconds.

Explanation:

Given the following data;

Distance = 1.65km to meters = 1.65 * 1000 = 1650 meters

We know that the speed of sound in steel is equal to 5200m/s

To find the time to hear the sound of the whistle;

Time = distance/speed

Substituting into the equation, we have

Time = 1650/5200

Time = 0.317 seconds.

Therefore, it will take him 0.317 seconds to hear the sound of the whistle.

3 0

3 years ago

A man is standing on the edge of a 20.0 m high cliff. He throws a rock horizontally with an initial velocity of 10.0 m/s.

kherson [118]

Answer:

<em>a. The rock takes 2.02 seconds to hit the ground</em>

<em>b. The rock lands at 20,2 m from the base of the cliff</em>

Explanation:

Horizontal motion occurs when an object is thrown horizontally with an initial speed v from a height h above the ground. When it happens, the object moves through a curved path determined by gravity until it hits the ground.

The time taken by the object to hit the ground is calculated by:

$\displaystyle t=\sqrt{\frac{2h}{g}}$

The range is defined as the maximum horizontal distance traveled by the object and it can be calculated as follows:

$\displaystyle d=v.t$

The man is standing on the edge of the h=20 m cliff and throws a rock with a horizontal speed of v=10 m/s.

The time taken by the rock to reach the ground is:

$\displaystyle t=\sqrt{\frac{2*20}{9.8}}$

$\displaystyle t=\sqrt{4.0816}$

t = 2.02 s

The rock takes 2.02 seconds to hit the ground

The range is calculated now:

$\displaystyle d=10\cdot 2.02$

d = 20.2 m

The rock lands at 20,2 m from the base of the cliff

5 0

3 years ago

What do you think causes the rising and sinking of molten rock in the mantle?

Svet_ta [14]

Answer:

Heyyy hope this helps

Convection currents describe the rising, spread, and sinking of gas, liquid, or molten material caused by the application of heat.

3 0

3 years ago

What is the difference between a neutralization reaction and a double-displacement reaction? (1 point) Double-displacement react

Alchen [17]

Answer:

Neutralization reactions always produce water and a salt.

Explanation:

There are different types of chemical reactions that occurs. Two of them are neutralization and double-displacement reaction. Neutralization reaction is the reaction between an acid and a base to give an acid salt and water as products. For example:

2NaOH (base) + H2SO4 (acid) → Na2SO4 (salt) + 2H2O (water)

On the other hand, Double displacement reaction is the reaction that involves an ion exchange between the reactants to form new products. This ionic exchange occurs in such a way that two reactants form two new products. For example:

2NaCl + Ca(NO3)2 → CaCl2 + 2NaNO3

Therefore, the major difference between these two types of reactions is that: NEUTRALIZATION MUST ALWAYS PRODUCE WATER AND SALT AS PRODUCTS.

3 0

3 years ago