Correct choices are marked in bold:
travel in straight lines and can bounce off surfaces --> TRUE, normally electromagnetic waves travel in straight lines, however they can be reflected by objects, bouncing off their surfaces
travel through space at the speed of light --> TRUE, all electromagnetic waves in space (vacuum) travel at the speed of light, 
)
travel only through matter --> FALSE; electromagnetic waves can also travel through vacuum
travel only through space --> FALSE, electromagnetic waves can also travel through matter
can bend around objects --> TRUE, this is what happens for instance when diffraction occurs: electromagnetic waves are bended around obstacles or small slits
move by particles bumping into each other --> FALSE, electromagnetic waves are oscillations of electric and magnetic fields, so no particles are involved
move by the interaction between an electric field and a magnetic field --> TRUE, electromagnetic waves consist of an electric field and a magnetic field oscillating in a direction perpendicular to the direction of motion of the wave
This problem is a piece o' cake, IF you know the formulas for both kinetic energy and momentum. So here they are:
Kinetic energy = (1/2) · (mass) · (speed²)
Momentum = (mass) · (speed)
So, now ... We know that
==> mass = 15 kg, and
==> kinetic energy = 30 Joules
Take those pieces of info and pluggum into the formula for kinetic energy:
Kinetic energy = (1/2) · (mass) · (speed²)
30 Joules = (1/2) · (15 kg) · (speed²)
60 Joules = (15 kg) · (speed²)
4 m²/s² = speed²
Speed = 2 m/s
THAT's all you need ! Now you can find momentum:
Momentum = (mass) · (speed)
Momentum = (15 kg) · (2 m/s)
<em>Momentum = 30 kg·m/s</em>
<em>(Notice that in this problem, although their units are different, the magnitude of the KE is equal to the magnitude of the momentum. When I saw this, I wondered whether that's always true. So I did a little more work, and I found out that it isn't ... it's a coincidence that's true for this problem and some others, but it's usually not true.)</em>
The vector, the x-component and the y-component form a rectangle triangle where the vector is the hypothenuse and the x and y components are the two sides.
Calling
the angle between the vector and the horizontal direction (x), the two sides are related to
by
where vy and vx are the two components on the y- and x-axis. Using vx=10 and vy=3 we find
And so the angle is
The weight of the object on mars is about 80n
Answer:
θ = 30°
Explanation:
Firts, the angle when the beam of light passes through the block cam be calculated using Snell Law:
<u>Where</u>:
n₁: is the index of refraction of the incident medium (air) = 1
θ₁: is the incident angle = 30°
n₂: is the medium 2 (plastic) = 1.46
θ₂: is the transmission angle
Hence, θ₂ is:
Now, when the beam of light re-emerges from the opposite side, we have:
n₁: is the index of refraction of the incident medium (plastic) = 1.46
θ₁: is the incident angle = 20.03°
n₂: is the medium 2 (air) = 1
θ₂: is the transmission angle
Hence, the angle to the normal to that surface (θ₂) is:
Therefore, we have that the beam of light will come out at the same angle of when it went in, since, it goes from air and enters to a plastic medium and then enters again in this medium to go out to air again. This was proved using the Snell Law.
I hope it helps you!
