Answer:
The answer is β=0,85 rads
Explanation:
As the ladder is leaning against the building, we can imagine there´s a triangle where 20ft is the hypotenuse and 15ft is the maximum vertical distance between the ladder and the ground, it means, the leg opposite to β which is the angle we need
Let β(betha) be the angle between the ladder and the ground
We also know that 
In this case we will need to find β, this way:

Then β=48,6°
We also have that 2πrads is equal to 360°, in this way we find how much β is in radians:

then we find β=0,85rads
Answer:
Explanation:
For sound level in decibel scale the relation is
dB = 10 log I / I₀ where I₀ = 10⁻¹² and I is intensity of sound whose decibel scale is to be calculated .
Putting the given values
61 = 10 log I / 10⁻¹²
log I / 10⁻¹² = 6.1
I = 10⁻¹² x 10⁶°¹

intensity of sound of 5 persons


= 10log 5 x 10⁶°¹
= 10( 6.1 + log 5 )
= 67.98
sound level will be 67.98 dB .
Answer:
The driver was not telling the truth because it is not possible for a car to hit another car from behind and generate a force to the sides that deflects it from its path.
Explanation:
First, we analyze the driver's statement.
The driver when arriving at the curve, is collided from behind by another car and deviates from his path and crashes into a tree. For the car to go to the tree there must be a force towards the tree.
The net force that causes the car to deviate must be formed by the sum of the motion vector of the first car plus the force that is directed towards the tree.
Here we verify that a car hitting from behind will not generate a force to the sides, but will generate a force in the same direction that the car moves, forward.
Answer:
folk dancing is old music and ball room is young dancing