Answer: Our body contains chemical potential energy from food we have eaten.
This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.
As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.
Explanation:
It is true that our food contains chemical bonds and these bonds have potential energy stored. So, when we eat food then our body acquires chemical potential energy.
When we rub our hands and arms then they form kinetic energy as atoms present within the skin of our hands come into motion. This rubbing of hands leads to the formation of heat which means thermal energy is being generated.
Thus, we can conclude that our body contains chemical potential energy from food we have eaten.
This chemical potential energy is transformed into the kinetic energy of our hands and arms as we rub our hands together.
As our hands move past each other and rub against each other, friction allows the kinetic energy to be transformed into thermal energy on the surface of our hands.
Answer:
<u>In an ionic bond , an element will have to lose or gain electrons.</u>
Explanation:
- Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.
- Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.
- <em>The atom that loses the electrons becomes a positively charged ion (cation), while the one that gains them becomes a negatively charged ion (anion).</em>
∴
- <em>The number of electrons an atom would gain or lose when forming ionic bonds cannot be zero.</em>
Answer:
D. Both occur between objects independently whether they are in contact or not.
Explanation:
- The gravitational force is a force that is exerted between two (or more) objects having mass. This force is always attractive and its magnitude is given by
where G is the gravitational constant, m1 and m2 are the two masses, and r is the distance between the two masses.
- The electrical force is a force that is exerted between two (or more) objects having electrical charge. It can be either attractive or repulsive, depending on the sign of the two charges, and its magnitude is given by
where k is the Coulomb's constant, q1 and q2 are the two charges, and r the distance between the two charges.
Looking at both formulas, we see that the two forces are present even when the two objects are not in contact with each other (in fact, r can assume any value in the formula). They are said to be non-contact forces. Therefore, the correct option is
D. Both occur between objects independently whether they are in contact or not.
