Draw a diagram to illustrate the problem as shown in the figure below.
h = height of the kite above ground.
By definition, the angle of elevation is

Therefore

Answer: 53° (nearest integer)
From tables, the density of mercury is
13545 kg/m^3 at 20°C,
13472 kg/m^3 at 50°C.
Because mass = density * volume, the mass of mercury at 20°C is
m = (13545 kg/m^3)*(0.002 m^3) = 27.09 kg
Let V = volume of mercury at 50°C.
Because the mass of mercury does not change, therefore at 50°C,
(13472 kg/m^3)*(V m^3) = 27.09
V = 27.09/13472 = 0.0020108 m^3
Answer: B. 0.002010812 m³
Answer:

Explanation:
The magnetic field can be find using the equation

You can cancel a element of v'



Solve to magnetic field

The charge and mass of the proton are:
, 
Replacing numeric


Answer:
the two balls will hit the ground at the same time.
Explanation:
The time of dropping, in the following equation, is related to both the distance travel s and the gravitational acceleration g, which are the same for both ball (if we neglect air resistance), no matter what their mass are.


So the time it takes to drop 2 balls are the same. They will hit the ground at the same time.
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