Answer:
Density relates a mass to its volume.
Density varies with temperature
Density determines if a substance floats or sinks.
Density may have units of grams per milliliter (g/mL)
Explanation:
Density 
is a characteristic property of a substance or material and is defined as the relationship between the mass 
of a body or substance and the volume 
it occupies:
This means the density is inversely proportional to the volume.
On the other hand, density is a scalar quantity and according to the International System of Units its unit is 
, although it can be also expressed in 
.
It should be noted that the density of a body is related to its buoyancy, a substance or body will float on another fluid if its density is lower. In addition, if the pressure of the substance remains constant, as the temperature increases, the density decreases; this means density varies with the temperature as well.
Answer:
The length of her shadow is changing at the rate -2 m/s
Explanation:
Let the height oh the street light, h = 22 ft
Let the height of the woman, w = 5.5 ft
Horizontal distance to the street light = l
length of shadow = x
h/w = (l + x)/x
22/5.5 = (l + x)/x
4x = l + x
3x = l
x = 1/3 l
taking the derivative with respect to t of both sides
dx/dt = 1/3 dl/dt
dl/dt = -6 ft/sec ( since the woman is walking towards the street light, the value of l is decreasing with time)
dx/dt = 1/3 * (-6)
dx/dt = -2 m/s
Answer:
Energy
A wave is a disturbance that carries energy from one place to another through matter and space.
Explanation:
A wave can be defined as a form of disturbance that carries energy from one place to another through matter and space.
The energy of wave depends on the frequency of the wave and the wavelength (lambda) of that particular wave.
Mathematically,
V = f × lambda
Answer:
R1 = 5.13 Ω
Explanation:
From Ohm's law,
V = IR............... Equation 1
Where V = Voltage, I = current, R = resistance.
From the question,
I = 2 A, R = R1
Substitute into equation 1
V = 2R1................ Equation 2
When a resistance of 2.2Ω is added in series with R1,
assuming the voltage source remain constant
R = 2.2+R1, and I = 1.4 A
V = 1.4(2.2+R1)................. Equation 3
Substitute the value of V into equation 3
2R1 = 1.4(2.2+R1)
2R1 = 3.08+1.4R1
2R1-1.4R1 = 3.08
0.6R1 = 3.08
R1 = 3.08/0.6
R1 = 5.13 Ω
