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Goryan [66]
3 years ago
14

Which of the following is NOT a example

Physics
1 answer:
solmaris [256]3 years ago
5 0

Answer:

B. a piece of paper being torn

Explanation:

A chemical change is one that cannot be reversed. This means the original properties of the substance or object cannot be restored.

If you cook a raw egg, it would turn into a boiled egg (or a poached egg, however it is being cooked). The reaction is irreversible, so you cannot turn the cooked egg back into a raw egg - it is basically impossible to 'uncook' an already cooked egg.

When you toast a piece of bread, it turns into toast. You can't 'untoast' it back into bread. The chemical changes have already occurred and cannot be undone.

If you tear a piece of paper, it is still paper. You are only ripping it, not changing anything about it. You could simply tape the torn bit back to the original bit, or glue it - either way, it is still paper and nothing has occurred to drastically change the physical state of it.

Therefore, B is not a chemical change.

You might be interested in
Physical and chemical properties of water​
posledela

(Not sure how many examples you need so I will put three for each)


Physical:

  1. As you now know, water in its natural condition is a colorless, odorless, and tasteless liquid. The hexagonal structure of water's crystals.
  2. The temperature at which a liquid's vapor pressure equals the pressure around it, turning the liquid into vapor, is known as the boiling point. We are aware that water reaches its boiling point at 100°C.
  3. The temperature at which a material transition from a liquid to a solid is known as the freezing point. The freezing point of water, which is 0°C or 32°F, is the temperature at which liquid water changes to solid ice.

Chemical:

  1. One of the most significant characteristics of water is its amphoteric tendency. Amphoteric refers to a substance's capacity to function as an acid or base. Water is neither acidic nor basic in its natural form. Its capacity to give and receive protons is the key justification. However, rainfall has a pH between 5.2 and 5.8, making it mildly acidic.
  2. Water is referred to be the all-purpose solvent. This is due to its chemical makeup, physical characteristics, high dielectric constant, and other factors that make it the most solvent material. It can attract other compound molecules, disabling their molecular forces and causing them to dissolve since hydrogen and oxygen both have positive and negative charges that are available.
  3. Water is a chemical molecule made up of two hydrogen atoms and one oxygen atom. The liquid condition of that substance is often referred to as water, and the solid and gas phases are respectively referred to as ice and steam.

6 0
2 years ago
Two objects have the same momentum. Do the velocities of these objects necessarily have (a) the same directions and (b) the same
NeX [460]

Answer:

(a) They must have same direction

(b) It is not necessary for them to have same magnitudes

Explanation:

(a)

Momentum is a vector quantity. It is the product of mass (scalar) and velocity (vector). Thus, if the direction of velocity is changed, then as a result the direction of momentum will also change or its magnitude or component in the same direction will change. Hence, for the two objects to have same momentum, the directions of their velocities must also be the same.

(b)

Since, the momentum is product of velocity and mass. It is possible that two bodies of different masses with different velocities might have same momentum, provided the direction of their velocities is same.

For example, take a body of mass 4 kg moving with speed 5 m/s. It will have a momentum of 20 N.s. Now, consider another body of mass 2 kg, moving with speed 10 m/s. It will also have a momentum of 20 N.s.

Thus, it is not necessary for two objects to have same magnitude of velocity to have same momentum.

3 0
3 years ago
A box of mass 50 kg is pushed hard enough to set it in motion across a flat surface. Then a 99-N pushing force is needed to keep
salantis [7]
The box is kept in motion at constant velocity by a force of F=99 N. Constant velocity means there is no acceleration, so the resultant of the forces acting on the box is zero. Apart from the force F pushing the box, there is only another force acting on it in the horizontal direction: the frictional force F_f which acts in the opposite direction of the motion, so in the opposite direction of F.
Therefore, since the resultant of the two forces must be zero,
F-F_f=0
so
F=F_f

The frictional force can be rewritten as
F_f = \mu m g
where m=50 kg, g=9.81 m/s^2. Re-arranging, we can solve this equation to find \mu, the coefficient of dynamic friction:
\mu =  \frac{F}{mg}= \frac{99 N}{(50 kg)(9.81 m/s^2)}  =0.20
4 0
3 years ago
Two large parallel metal plates are 1.6 cm apart and have charges of equal magnitude but opposite signs on their facing surfaces
Flauer [41]

Answer:

787.5 V/m

Explanation:

the formula to find the electric field in the region between the plates is

E = V/d

where

V=the voltage supplied by the battery (potential)

d=distance between the plates.

E=electric field

Given:

V= 6.3 V

d= 1.6cm/2=> 0.016m/2

E= V/d=> 6.3/(0.016/2)

E= 787.5 V/m

Therefore, the electric field in the region between the plates is 787.5 V/m

7 0
3 years ago
Read 2 more answers
two blocks are held together with a compressed spring between them on the surface of a slippery table .one block has three times
Marina CMI [18]

Explanation:

The initial kinetic energy KE_0 for both blocks is zero. Let m_1= m and m_2 =3m. So using the conservation law of linear momentum, we can write

0 = m_1v_1 - m_2v_2

or

v_2 = \dfrac{m_1}{m_2}v_1 = \dfrac{m}{3m}v_1 = \dfrac{1}{3}v_1

The final kinetic energies for the two masses are

KE_1 = \frac{1}{2}m_1v_1^2 = \frac{1}{2}mv_1^2

KE_2 = \frac{1}{2}m_2v_2^2 = \frac{1}{2}(3m)(\frac{1}{3}v_1)^2 = \frac{1}{2}m(\frac{1}{3}v_1^2)

Therefore, the ratio of their kinetic energies is

\dfrac{\Delta KE_2}{\Delta KE_1}  = \dfrac{\frac{1}{2}(\frac{1}{3}v_1^2)}{\frac{1}{2}v_1^2} = \dfrac{1}{3}

4 0
3 years ago
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