During Physical Change there would be a re-arrangements of atoms or molecules, changes of the arrangement may be change in the distance between atoms or molecules, change in the crystal form, .....etc
for example: water when heated it undergoes a Physical Change and turn into vapor, this means the heat cause the distance between water molecules to increase, so it transferred from the liquid form to the gas form.
NOTE that in Physical Change there is no change in the chemical structure and the material retains all its chemical properties, and no new compounds are produced.
again, A physical change is any change not involving a change in the substance's chemical identity. Matter undergoes chemical change when the composition of the substances changes: one or more substances combine or break up (as in a relationship) to form new substances.Physical changes occur when objects undergo a change that does not change their chemical nature. A physical change involves a change in physical properties. Physical properties can be observed without changing the type of matter. Examples of physical properties include: texture, shape, size, color, odor, volume, mass, weight, and density.
BUT in Chemical Change ( or Chemical Reaction ) there would be change in the chemical nature of the material undergoing a Chemical Change with the production of new compounds.
D=m/V therefore the answer is 120/200 or 0.6
It has to due with numbers so I would say the last one!
Answer:
The wavelength of the infrared wave is <u>0.0001 m</u>.
Explanation:
Given:
Frequency of an infrared wave is, 
We know that, infrared waves are electromagnetic waves. All electromagnetic waves travel with the same speed and their magnitude is equal to the speed of light in air.
So, speed of infrared waves coming from the Sun travels with the speed of light and thus its magnitude is given as:
Where, 'v' is the speed of infrared waves and 'c' is the speed of light.
Now, we have a formula for the speed of any wave and is given as:
Where, 
Now, rewriting the above formula in terms of wavelength, 
, we get:
Now, plug in 
for 'v', 
for 'f' and solve for . This gives,
Therefore, the wavelength of the infrared wave is 0.0001 m.
Answer:
20,850 N
Explanation:
We can solve the problem by using second Newton's Law:
where
F is the force
m is the mass
a is the acceleration
In this problem, we have:
m = 70 kg is the mass
is the acceleration (which is negative, because it is a deceleration)
So, we can use the equation above to find the force:
and the negative sign simply means that the force is in the opposite direction to the motion.
