You have to draw a mathematical spatial axes .in order to judge is it right or not .. well you have to draw the crest and trough both of 1 cm in length and the total wavelength (same phase on the wave of 2 cm ) something like this
Let's calculate the angle between two spots, 0.5 cm apart,
that are 10m away from you.
1 m = 100 cm
10m = 1,000 cm
The angle between the two spots is very very close to the angle
whose tangent is
0.5cm/1,000cm = 0.0005 .
That angle is tan⁻¹(0.0005) = 0.0005 radian = 0.029 degree .
Matilda is looking at two stars that appear to be 0.001 radian apart.
That's (0.001 / 0.0005) = 2 = TWICE as far apart as Arthur can distinguish.
As long as Arthur and Matilda are on the same planet while looking at
these two stars ... or as long as they're even in the same solar system ...
Arthur will have no trouble separating them.
Explanation:
Density is mass divided by volume:
D = M / V
Given V = 79000 cm³ and D = 13.6 g/cm³:
13.6 g/cm³ = M / (79000 cm³)
M = 1,074,400 g
M = 1,074 kg
Round as needed.
The answer would be:
Pulling a trailer up a hill
Here is why:
In physics, work is computed by the formula:
W = Fd or F(cosΘ)d
Where: F = Force applied on the object
d =displacement
So in order for work to be done, the object needs to be displaced. In the case of the trailer, the trailer is being pulled and it is travelling in the direction of the force applied.
The other options the object is not displaced. Even if you exert a force, if the displacement remains the same, then it will always be zero, so the force times displacement will be 0, hence no work is done.