The density of the material would be 4.1 g/cm³.
Density is calculated by dividing the mass by the volume.
D=m÷v
D=45 g÷11 cm³
D=4.1 g/cm³
Speed= distance/ time so distance = speed * time= 28 * 20= 560m .. so the answer is 560m.. l hope it helped :)
Answer:
The minimum thickness = 83.92 nm
Explanation:
The relation between the wavelength in a particular medium and refractive index 
where ;
= wavelength of the light in vacuum
n = refractive index of medium with respect to vacuum
For one phase change :

Replacing 1.43 for n and 480 nm for λ; we have:

t = 83.92 nm
Thus; the minimum thickness = 83.92 nm
To solve this problem we will use the concepts related to power, defined as the amount of energy applied over a period of time.
The energy in this case is the accumulated in the form of potential energy, over a period of time. Thus we will have that the mathematical expression of the power can be expressed as

Here,
E = Energy
t = time
As the energy is equal to the potential Energy we have tat

The weight (mg) of the man is 700N, the height (h) is 8m and the time is 10s, then:


Therefore the correct answer is A.
... find length
(way 1) determine acceleration using force
only force act on skier is mg vertically. spilt vector we get force along the incline = mgsin(10) and f= ma so
ma = mgsin(10) or a = gsin(10)
a (along the incline)= gsin(10) = 10sin(10) = 1.74
v^2 = u^2 + 2as
15^2 = 3^2 + 2(1.74)s
s = 62.06 m
(way 2) using conservation of energy
energy (KE+PE) on top = energy at bottom
0.5m3^2 + mgh = 0.5m15^2 +0
h (height of incline) = (112.5 - 4.5)/10 = 19.8 m
length of incline = h/sin(10) = 62.2 m ; trigonometry
... find time
s = (u+v)t/2
t = 2s/(u+v) = 2(62.2)/(3+15) = 6.91 s