What happens to a chemical reaction when the temperature is increased ?

Answer: the correct options are

- were once connected

- are slowly drifting

Explanation: The continent is the main land mass of the earth which includes the following:

- Asia, Africa, Europe, Australia, North America, South America, and Antarctica.

These continents were once connected forming a supercontinent called PANGAEA

during the late palaeozoic and early mesozoic eras, millions of years ago.

Alfred Wegener, who is a German meteorologist, in 1912 came up with a hypothesis that the continents are slowly drifting the earth. He called the movement continental drift.

The continents rest on massive slabs of rock called tectonic plates. The plates are always moving and interacting in a process called plate tectonics. In recent studies, through the science of plate tectonics, we where able to understand the mechanism through which continental drift occurs. The mechanism includes:

- processes of seafloor spreading,

- rift valley formation, and

- subduction (where heavier tectonic plates sink beneath lighter ones).

Answer:

Were once connected, and Are slowly drifting

Explanation:

It's called the continental drift, At first, Wegener's theory was dismissed. No one believed that the continents moved. During the 1920s, another scientist named Arthur Holmes suggested that the magma in the earth's mantle moved through convection currents. As hot magma rose toward the crust, it cooled and then sank back down. The cycle continued over and over, causing motion that was powerful enough to move the continents. Like Wegener's theory, Holmes' idea was not accepted by the scientific community. Forty years later, geologists compared mineral and fossil samples from Africa to those in South America. The samples matched perfectly. Today, the theory of continental drift is supported by a large amount of data and evidence. The continents as a whole was once called Pangaea.

As per the question the mass of the object is given as 70 kg.

The height of the object from ground is 8 m.

We are asked to calculate the potential energy of that object.

The potential energy of a object is the energy gained by the body due to its position or configuration. The energy due to the position of object from the surface is called gravitational potential energy .

If a body of mass m is at a height of h from the ground,then its potential energy is calculated as -

                               potential energy

where g is the acceleration due to gravity.

    we have been given h= 8 m and m= 70 kg

we know that acceleration due to gravity g =9. 8 m/s^2

                                        ⇒

                                                    =5488 Joule

Here Joule is the unit of energy.

Answer;

The comparison that would be best is;

They are in the same group because they have similar chemical properties, but they are in different periods because they have very different atomic numbers.

Explanation;

• Beryllium (Be) is an element is the periodic table with an atomic number of 4, which means it has 4 protons in the nucleus and also 4 electrons in the energy levels, since the number of protons is equal to the number of electrons.
• Beryllium has an electron configuration of 2: 2, which means it has two valence electrons, and has two energy levels which means it occupies period two of the periodic table, and group two of the periodic table.
• Barium (Ba) on the other had, has an atomic number of 56, which means it has 56 protons and 56 electrons. Thus it has an electron configuration of; 2;8;18;18;8;2;  this shows that it has 6 energy levels thus occupies period 6 and is in group two since it has two valence electrons.

Answer:

= 230.8 ohms

Explanation:

From ohms law, V = IR

R=V/I

R = 120 ÷ 0.520

R = 230.8 ohms

Answer:

b. The final temperature of the coffee cup will be higher than 25°C but less than 75°C.

Explanation:

We know in thermal equilibrium.

Heat loss by one object = Heat gain by other object.

Now, heat is loss by the object whose temperature is higher than other because heat travels from high temperature to other.

And the object who gain heat its temperature increases till both body reach same temperature.

In this case, water loss heat, therefore its temperature decreases.

Similarly , metal block is at low temperature so its temperature increases.

Therefore , both water and metal block must have temperature less than and to have thermal equilibrium.  

Answer

Force is necessary to stretch a spring 0.5 m when the spring constant is 190 N/m is 95 N .

Explanation:

By using Hookes law .

The force required to extend a spring is directly proportional  to the distance you stretch it .

Thus

F = kx

Where F is force , k is spring constant and x is the extension of spring .

As given

A spring is stretch to 0.5 m .

The spring constant is 190 N/m .

x = 0.5 m

k = 190 N /m

Putting all the values in the formula

F = 190 × 0.5

  = 95 N

Therefore the force is necessary to stretch a spring 0.5 m when the spring constant is 190 N/m is 95 N .