Answer:
It was proposed by Isaac Newton
Explanation:
The law of universal attraction of expression
F =
G m1m2 / r ^ 2
where G is a constant, m₁ and m₂ are the masses of the bodies and r the distance between them.
It was proposed by Isaac Newton
With this law Newton explained that the force that pulls the moon towards the earth is the same as that which attracts an apple towards the earth
The diagram is missing; however, we know that the intensity of a sound wave is inversely proportional to the square of the distance from the source:

where I is the intensity and r is the distance from the source.
We can assume for instance that the initial distance from the source is r=1 m, so that we put

The intensity at r=3 m will be

Therefore, the sound intensity has decreased by a factor

.
Answer:
North
Explanation:
In an electromagnetic wave, the direction of the wave, the direction of the electric field and the direction of the magnetic field are all perpendicular to each other.
Therefore, we can find the direction of the magnetic field by using the right hand rule. We have:
- Index finger: direction of motion of the wave --> toward the center of Earth
- middle finger: direction of the electric field --> west
- thumb: direction of the magnetic field --> north
So, the magnetic field points north.
Velocity of the sled is 3.2 m/s
Answer:
The minimum coefficient of friction required is 0.35.
Explanation:
The minimum coefficient of friction required to keep the crate from sliding can be found as follows:


Where:
μ: is the coefficient of friction
m: is the mass of the crate
g: is the gravity
a: is the acceleration of the truck
The acceleration of the truck can be found by using the following equation:


Where:
d: is the distance traveled = 46.1 m
: is the final speed of the truck = 0 (it stops)
: is the initial speed of the truck = 17.9 m/s
If we take the reference system on the crate, the force will be positive since the crate will feel the movement in the positive direction.

Therefore, the minimum coefficient of friction required is 0.35.
I hope it helps you!