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2 years ago

Explain why the life cycle of a star can be compared to the life style of a human

1 answer:

6 0

A star is born when clouds of dust and elements are gathered together in a certain space due to gravity, more and more mass and therefore pressure builds. When the pressure becomes enough to overcome the electronic repulsive force between two hydrogen nuclei, they are forced together and massive amounts of energy are given off forming helium atoms. This energy is then used to fuse other nuclei together. This could be compared to the way human life starts, where instead of 2 nuclei joining together to start a life cycle, two gametes, or sex cells are joined together. Also at the start of both a star and persons life, we are weak and we gain strength until we reach the height of our existence, then humans slowly become less efficient at doing what they do until eventually they cannot sustain themselves any further.

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Which object has the least amount of kinetic energy? a car driving down a road a soccer ball rolling down a hill a bicycle locke

mars1129 [50]

<span> a bicycle locked to a bike rack im pretty sure</span>

7 0

2 years ago

Read 2 more answers

Two pith balls hang side by side close to each other without touching as shown in the figure below. They are both neutral to beg

Mila [183]

When a plastic rod is rubbed with wool, charging by friction occurs.

This is one of the three mechanisms of charging an object: in this particular case, as the rod is rubbed with the wool, electrons jump from the wool to the rod.

As a result, the plastic rod will remain with an excess of electrons (negative charge), while the wool will remain with a lack of electrons (positive charge).

However, the number of electrons gained by the rod is equal to the number of electrons given off by the wool: therefore, the total net charge of the system rod + cloth has not changed.

When the rod touches sphere A, some electrons are transferred from the rod to the sphere (this method of charging is called charging by conduction).

Then, the sphere A will also remain negatively charged, as well as the plastic rod.

Later, the rod is brought close to sphere A without touching it: here, the electrons in the rod repel the electrons in the sphere (like charges repel each other), so the rod and the sphere will repel each other.

Before part b), the negative charge on the plastic rod was equal to the positive charge on the wool.

After part b), the plastic rod has given off part of its electrons to sphere A. As a result, the negative charge on the plastic rod will be now less than the positive charge on the wool.

Therefore, the net charge of the rod + wool system will now be positive.

The electrostatic force between two charged object is:

- Attractive if the charges on the objects have opposite sign

- Repulsive if the charges on the objects have same sign

Since sphere A is charged negatively, when it is brought close to sphere B, the electrons in sphere B will be attracted on the opposite side relative to sphere A, while the positive charges will migrate close to sphere A. Therefore, the two spheres will attract each other, since opposite charges attract each other.

When the plastic rod (which is negatively charged) touches sphere B, some electrons are transferred to sphere B (charging by induction). As a result, charge B will also be negatively charged now, as it has an excess of electrons.

At the same time, sphere A is also negatively charged. Therefore, as like charges repel each other, this means that the two spheres will now repel each other.

The net charge of the rod and the two spheres is negative.

In fact, the electrons given off by the rod to the two spheres were initially on the rod itself: this means that the total net charge of the rod + 2 spheres is equal to the net charge on the rod before the process.

Since the net charge on the rod before the process was negative, then the net charge of the system consisting of the rod + 2 spheres must be negative as well.

When a glass rod is rubbed with silk, charging by friction occurs, similar to part a). However in this case, the glass rod gives off electrons to the silk: therefore, the glass rod remains positively charged.

Later, the glass rod touches sphere B: as a result, positive charge is transferred from the rod to sphere B, so sphere B will remain positively charged.

In the meantime, sphere A is negatively charged: since opposite charges attract each other, this means that now sphere A and sphere B will attract each other.

When the two spheres are moved a bit further apart, the attractive force between them decreases a bit. In fact, the electrostatic force between two charged objects is given by

$F=k\frac{q_1 q_2}{r^2}$

where

k is the Coulomb's constant

q1, q2 are the charges on the two objects

r is the separation between the objects

As we can see, the force is inversely proportional to the square of the distance: therefore, if the separation between the spheres increases, the force will decrease.

4 0

2 years ago

5. Graph A plots a race car's speed for 5 seconds. The car's

Nastasia [14]

The answer for the cars speed is tue

5 0

2 years ago

A remote controlled toy car starts from rest and begins to accelerate in a straight line. The figure below represents "snapshots

Nikolay [14]

(a). The car's average velocity between t = 1.0s to t = 1.5s will be - $1\;m/s$

(b). The car's acceleration at t = 1.5s will be - $0.4\;m/s^{2}$

(c). Car's speed is increasing with time.

We have a a remote controlled toy car that starts from rest and begins to accelerate in a straight line.

We have to determine -

The car's average velocity (in m/s) in the interval between -

t = 1.0 s to t = 1.5 s.

The car's acceleration at t = 1.5 s.
Determining whether car's speed increasing or decreasing with time.

<h3>What is Acceleration?</h3>

The rate of change of velocity with respect to time is called Acceleration. Mathematically -

$$a=\frac{dv}{dt}$

According to the question, we have the following data for the Car -

t = 0s → x = 0m

t = 0.5s → x = 0.1m

t = 1.0s → x = 0.4m

t = 1.5s → x = 0.9m

t = 2.0s → x = 1.6m

PART - A

The car's average velocity between t = 1.0s to t = 1.5s will be -

$$v_{avg} = \frac{0.9-0.4}{1.5-1}= 1 m/s$

PART - B

Velocity at t = 1.5 s will be -

$$v(1.5)=\frac{0.9}{1.5}= 0.6\;m/s$

The car's acceleration at t = 1.5s will be -

$$a(1.5) = \frac{v}{t} = \frac{0.6}{1.5} = 0.4\;m/s^{2}$

PART - C

Since, the acceleration of the car is positive, this means that the car is accelerating in the forward direction. Hence, its speed is increasing with time.

[ The following data was missing in your answer. The complete question would include this data also -

t = 0s → x = 0m

t = 0.5s → x = 0.1m

t = 1.0s → x = 0.4m

t = 1.5s → x = 0.9m

t = 2.0s → x = 1.6m ]

To solve more questions on Kinematics, visit the link below-

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7 0

1 year ago

Read 2 more answers