I think they decrease echo and reduce noise, they do this by either absorbing vibrations or by scattering the sound so that echoes arrive at different times rather than reverberating as a standing wave. An echo is a reflection of a sound that arrives at the listener with a delay after the direct sound. The delay is usually proportional to the distance of the reflecting surface from the source and the listener.
Answer:
(A) because there are the same number of atoms of each element shown on both sides
Explanation:
The Law of conservation of mass says that in a reaction the matter of the products should be equivalent to the matter of the reactants and the mass of the system should remain constant over time.
In a chemical reaction, while atoms bond is breaking of 1 substance than new bonds are formed in another substance and new substances are formed. However, in the overall reaction, they keep the same elements, no new elements can go and come from the outside. For example:
HCl + NaOH -----> NaCl + H2O
In this reaction, on both sides the same number of atoms of each element are present.
The change in momentum of the car is 45,000 kg m/s
Explanation:
The change in momentum of an object is given by:

where
m is the mass of the object
u is its initial velocity
v is its final velocity
For the car in this problem, we have
m = 900 kg
u = 30 m/s
v = 80 m/s
Therefore, the change in momentum is:

Learn more about momentum:
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Answer:
a)
= 692 N
b)
= 932 N
Explanation:
a)
According to newton's second law of motion, acceleration of an object is directly proportional to the net force acting on it. When there is no net force force acting on the body, there is no acceleration. A force is a push or a pull, and the net force ΣF is the total force, or sum of the forces exerted on an object in all directions.
∝ a
= ma
= ma
Given data:
= 800 N
Mass = m = 90 kg
acceleration = a = 1.2 m/s²
= ?
800 -
= (90)(1.2)
= 692 N
b)
According to newton's second law of motion,
∝ a
= ma
= ma
Given data:
If we assume the same friction and acceleration between player's feet and ground as calculated in part a
= 692 N
acceleration = a = 1.2 m/s²
We take the equal mass to the total mass of both the players because when the winning player push losing player backward, he exert force on the ground not only due to his mass but also due to the mass of losing player.
Mass = M = m₁ + m₂ = 110 kg + 90 kg
= 200 kg
= ?
- 692 N = (200)(1.2)
= 692 + 240
= 932 N
Answer:
a

b

Explanation:
From the question we are told that
The current is 
The length of one side of the square 
The separation between the plate is 
Generally electric flux is mathematically represented as

differentiating both sides with respect to t is

=> 
Here
is the permitivity of free space with value

=> 
=> 
Generally the displacement current between the plates in A

=> 