A. Through the direct contact of particles
Answer:
The specific gravity of the unkown liquid is 15.
Explanation:
Gauge pressure, at the bottom of the tank in this case, can be calculated from

where
and
are the height of the column of oil and the unkown liquid, respectively. Writing for
, we have

Relative to water, the unknow liquid specific weight is 15 times bigger, therefore this is its specific gravity as well.
The yellow light indicates that you have to slow down and slowly come to a stop. You slow your car until light completely turns red, then you stop at red and wait for the light
Answer: The weight of the air displaced by the balloon is less than the volume of the balloon.
Explanation:
A hot air balloon is a cloth wrap that contains several thousand cubic meters of air inside (a large volume of air). The burner heats the liquid propane to a gaseous state to generate a huge flame, which can reach more than 3 meters, thus heating the air mass inside the balloon. In this way,<u> its density is modified with respect to the air that surrounds it</u>, because the hot air is lighter than the outside air (less dense), causing the balloon to rise and float.
Now, if we know that the density of a body
is directly proportional to its mass
and inversely proportional to its volume
:

We can deduce that <u>by increasing the volume of the body, its density will decrease.</u>
This is proof of <em><u>Archimedes' Principle</u></em>:
<em>A body totally or partially immersed in a fluid at rest, experiences a vertical upward thrust equal to the mass weight of the body volume that is displaced.</em>
In this case the fluid is the air outside. So, the warm air inside the balloon, being less dense, will weigh less than the outside air and therefore will receive an upward pushing force or thrust that will make the balloon ascend.
Answer:
Explanation:
There are two types of collision.
(a) Elastic collision: When there is no loss of energy during the collision, then the collision is said to be elastic collision.
In case of elastic collision, the momentum is conserved, the kinetic energy is conserved and all the forces are conservative in nature.
The momentum of the system before collision = the momentum of system after collision
The kinetic energy of the system before collision = the kinetic energy after the collision
(b) Inelastic collision: When there is some loss of energy during the collision, then the collision is said to be inelastic collision.
In case of inelastic collision, the momentum is conserved, the kinetic energy is not conserved, the total mechanical energy is conserved and all the forces or some of the forces are non conservative in nature.
The momentum of the system before collision = the momentum of system after collision
The total mechanical energy of the system before collision = total mechanical of the system after the collision