The component of waves must have same frequency and phase.
when the component of waves vibrate at the same rate and attain maximum point at the same time, reinforcement of the waves amplitude occur to cause a constructive interference.However, when the two waves are out of phase where one is at minimum when the other is at maximum a destructive interference happens.
We all know that the sound travels faster through solids and then liquids and then through gases.
As far as i know solids are the medium through which the sound travels fast.
But in some websites I saw that as the density increases , the velocity of the sound decreases.If this statement is correct , how come the sound travels fastest through solids (since they have higher density)
From this it is clear that not only sound as compression wave But also in the form of Shear wave travels in Solids
This makes it easier for sound to travel with higher speed in solids
Resonance:
The resounding recurrence is the recurrence at which a bit of metal, plastic or whatever else swings/vibrates with minimal measure of vitality input. Think about a man on a play area swing. You realize that it requires next to no push to keep the individual swinging. The recurrence at which they swing forward and backward is their full recurrence. In the event that you endeavor to influence them to swing speedier or slower, it will take altogether more vitality.
Resonating Panels:
This kind of clamor is caused when the bass notes are an indistinguishable recurrence from the thunderous recurrence of a metal or plastic board. To stop or decrease the commotion related with this kind of issue, you can do two or three things.
Rattling:
This sort of commotion would be caused when 2 bits of metal, plastic, whatever... are sufficiently close to hammer into each other when they resound. This is most likely best illuminated by filling the hole between the two vibrating parts with silicone sealant or shut cell froth climate stripping. The climate stripping is a superior arrangement in places like behind the tag. On the off chance that you have a tag outline, you can get some truly thin climate stripping and put between the casing and the plate.
Complete question
A 2700 kg car accelerates from rest under the action of two forces. one is a forward force of 1157 newtons provided by traction between the wheels and the road. the other is a 902 newton resistive force due to various frictional forces. how far must the car travel for its speed to reach 3.6 meters per second? answer in units of meters.
Answer:
The car must travel 68.94 meters.
Explanation:
First, we are going to find the acceleration of the car using Newton's second Law:
(1)
with m the mass , a the acceleration and 
the net force forces that is:
(2)
with F the force provided by traction and f the resistive force:
(2) on (1):
solving for a:
Now let's use the Galileo’s kinematic equation
(3)
With Vo te initial velocity that's zero because it started from rest, Vf the final velocity (3.6) and 
the time took to achieve that velocity, solving (3) for :
