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3 years ago

Why do things become hot or cold? Relate to Thermal Energy and The Law of Conservation of Energy

Physics

1 answer:

Mekhanik [1.2K]3 years ago

4 0

<u>Answer:</u>

Things become hot and cold because of the transfer of energy.

<u>Explanation:</u>

The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.

When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.

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Why is cheese only strechy when its hot not when its cold (i spelt stretchy wrong but i dont want to change it cuz that would ta

IgorC [24]

That is a really good question, cheese is stretchy when it is hot is because when you heat it up, it liquefies which makes it stretch. it doesn't stretch when it is cold because it is a solid and solids usually do not stretch.

8 0

3 years ago

If your friend drops a chocolate bar to you from a height of 5.0 m above your hands,

Sladkaya [172]

Answer:

Explanation:

Using the equation of motion S = ut+1/2gt² to solve the problem where;

u is the initial velocity of the chocolate = 0m/s

t is the time taken

g is the acceleration due to gravity = 9.81m/s²

S is the height of fall = 5.0m

Substituting the given parameter into the formula to get the time t we have;

5 = 0(t)+1/2(9.81)t²

5 = 4.905t²

t² = 5/4.905

t² = 1.019

t = √1.019

t = 1.009 secs

<em>Hence it will take 1.01 secs for me to catch the chocolate bar</em>

6 0

4 years ago

A space probe is fired as a projectile from the Earth's surface with an initial speed of 2.05 104 m/s. What will its speed be wh

Elanso [62]

Answer:

The value is $v = 2.3359 *10^{4} \ m/s$

Explanation:

From the question we are told that

The initial speed is $u = 2.05 *10^{4} \ m/s$

Generally the total energy possessed by the space probe when on earth is mathematically represented as

$T__{E}} = KE__{i}} + KE__{e}}$

Here $KE_i$ is the kinetic energy of the space probe due to its initial speed which is mathematically represented as

$KE_i = \frac{1}{2} * m * u^2$

=> $KE_i = \frac{1}{2} * m * (2.05 *10^{4})^2$

=> $KE_i = 2.101 *10^{8} \ \ m \ \ J$

And $KE_e$ is the kinetic energy that the space probe requires to escape the Earth's gravitational pull , this is mathematically represented as

$KE_e = \frac{1}{2} * m * v_e^2$

Here $v_e$ is the escape velocity from earth which has a value $v_e = 11.2 *10^{3} \ m/s$

=> $KE_e = \frac{1}{2} * m * (11.3 *10^{3})^2$

=> $KE_e = 6.272 *10^{7} \ \ m \ \ J$

Generally given that at a position that is very far from the earth that the is Zero, the kinetic energy at that position is mathematically represented as

$KE_p = \frac{1}{2} * m * v^2$

Generally from the law energy conservation we have that

$T__{E}} = KE_p$

$2.101 *10^{8} m + 6.272 *10^{7} m = \frac{1}{2} * m * v^2$

=> $5.4564 *10^{8} = v^2$

=> $v = \sqrt{5.4564 *10^{8}}$

=> $v = 2.3359 *10^{4} \ m/s$

4 0

3 years ago

Imagine two billiard balls on a pool table. Ball A has a mass of 7 kilograms and ball B has a mass of 2 kilograms. The initial v

olga_2 [115]

A) the final velocity = 66/9 m/s.
b) The total momentum before and after collision is the same because energy is destroyed or made.
Thanks brainly. <span />

7 0

4 years ago

If two particles have equal charges and are placed near one another, how

navik [9.2K]

Answer: C) The two particles will move away from each other

Explanation:

When two electrically charged bodies come closer, appears a force that attracts or repels them, depending on the sign of the charges of this two bodies.

This is stated by Coulomb's Law:

"The electrostatic force $F_{E}$ between two point charges $q_{1}$ and $q_{2}$ is proportional to the product of the charges and inversely proportional to the square of the distance $d$ that separates them, and has the direction of the line that joins them"

Mathematically this law is written as:

$F_{E}= K\frac{q_{1}.q_{2}}{d^{2}}$

Where $K$ is a proportionality constant.

Now, if $q_{1}$ and $q_{2}$ have the same sign charge (both positive or both negative), a repulsive force will act on these charges.

5 0

4 years ago