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3 years ago

Comet tails _____.

Physics

2 answers:

Troyanec [42]3 years ago

7 0

Answer:

A) Always point towards the sun

elena-s [515]3 years ago

3 0

Answer:

A always point toward the sun

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What did Bohr hypothesize about the atom?

Svetach [21]

Bohr described the Planetary theory. the atom has a positive nucleus with electrons orbiting around them like planets.

7 0

4 years ago

Point A of the circular disk is at the angular position θ = 0 at time t = 0. The disk has angular velocity ω0 = 0.17 rad/s at t

statuscvo [17]

Given that,

Angular velocity = 0.17 rad/s

Angular acceleration = 1.3 rad/s²

Time = 1.7 s

We need to calculate the angular velocity

Using angular equation of motion

$\omega=\omega_{0}+\alpha t$

Put the value in the equation

$\omega=0.17+1.3\times1.7$

$\omega=2.38(k)\ m/s$

We need to calculate the angular displacement

Using angular equation of motion

$\theta=\theta_{0}+\omega_{0}t+\dfrac{\alpha t^2}{2}$

Put the value in the equation

$\theta=0+0.17\times1.7+\dfrac{1.3\times1.7^2}{2}$

$\theta=2.1675\times\dfrac{180}{\pi}$

$\theta= 124.18^{\circ}$

We need to calculate the velocity at point A

Using equation of motion

$v_{A}=v_{0}+\omega\times r$

Put the value into the formula

$v_{A}=0+2.38(k) \times0.2(\cos(124.18)i+\sin(124.18)j))$

$v_{A}=0.476\cos(124.18)j+0.476\sin(124.18)i$

$v_{A}=(-0.267j-0.393i)\ m/s$

We need to calculate the acceleration at point A

Using equation of motion

$a_{A}=a_{0}+\alpha\times r+\omega\times(\omega\times r)$

Put the value in the equation

$a_{A}=0+1.3(k)\times0.2(\cos(124.18)i+\sin(124.18)j)+2.38\times2.38\times0.2(\cos(124.18)i+\sin(124.18)j)$

$a_{A}=0.26\cos(124.18)i+0.26\sin(124.18)j+(2.38)^2\times0.2(\cos(124.18)i+\sin(124.18)j)$

$a_{A}=-0.146j-0.215i−0.636i+0.937j$

$a_{A}=0.791j-0.851i$

$a_{A}=-0.851i+0.791j\ m/s^2$

Hence, (a). The velocity at point A is $(-0.267j-0.393i)\ m/s$

(b). The acceleration at point A is $(-0.851i+0.791j)\ m/s^2$

3 0

4 years ago

A beach ball with a volume of 5,000 cm3 is pushed underwater. What is the magnitude of the buoyant force pushing upwards? The de

Kobotan [32]

<h2>Hello!</h2>

The answer is:

The buoyant force is equal to 49N.

The buoyant force is the force that pushes upwards and object when it's submerged in water, this force is always trying to move the object to the surface of the liquid or water. We must consider that the volume of water or liquid displaced is equal to the volume of the submerged object.

We can calculate the buoyant force using the following formula:

$F_{B}=Density*VolumeDisplaced*GravityAcceleration$

Where,

Density is the density of the water or liquid.

Volume displaced is equal to the volume of the submerged object.

Gravity acceleration is the acceleration due to gravity.

So, from the statement we know that:

$VolumeDisplaced=BeachBallVolume=5000cm^{3}\\\\Density=1\frac{gram}{cm^{3} }=\frac{0.001kg}{cm^{3} }\\\\g=9.8\frac{m}{s^{2} }$

Now, substituting and calculating we have:

$F_{B}=Density*VolumeDisplaced*GravityAcceleration$

$F_{B}=0.001\frac{kg}{cm^{3}*} *5000cm^{3}*9.8\frac{m}{s^{2} }$

$F_{B}=49\frac{Kg.m}{s^{2}}=49N$

Hence, we have that the correct answer is:

The buoyant force is equal to 49N.

Have a nice day!

7 0

4 years ago

Atoms are split at power plant to create electricity*

Rudiy27

Answer:

B. Nuclear to Electrical

Explanation:

Atoms are split at power plants to create electricity. The energy conversion in this process is from nuclear to electrical energy.

When atoms are split, nuclear energy is released.
Some part of the mass of the atom is converted to energy.
The nuclear energy released is expressed as heat energy.
This energy is used to heat water in boilers when produces steam that are used to drive the movement of turbines.
This in turn generates electricity.

8 0

3 years ago

The bearing of a lighthouse from a ship was found to be N 37 degrees E. After the ship sailed 2.5 miles due south, the new beari

ella [17]

Answer:

The distance between the lighthouse and the ship

from the start position A = 5.08 miles

from the Final point B = 7.23 miles

Explanation:

Note: Refer the figure

Let the position of the lighthouse be 'L'

Given:

When the ship is at the position A, ∠DAL=37°

Now, when the ship sails through a distance of 2.5 i.e at position B

mathematically,

AB=2.5 miles

∠ABL=25°

Now,

∠DAL + ∠LAB = 180°

37° + ∠LAB = 180°

∠LAB = 180° - 37° = 143°

Also, In ΔLAB

∠LAB + ∠ABL + ∠ALB = 180°

143° + 25° + ∠ALB = 180°

∠ALB = 180° - 143° - 25° = 12°

Now using the concept of the sin law

In ΔLAB

$\frac{AL}{sin25^o}=\frac{2.5}{sin12^o}$

AL = 5.08 miles

and,

$\frac{BL}{sin143^o}=\frac{2.5}{sin12^o}$

BL = 7.23 miles

hence,

The distance between the lighthouse and the ship

from the start position A = 5.08 miles

from the Final point B = 7.23 miles

5 0

3 years ago