Answer:
All statement are correct.
Explanation:
1. Electric field lines are the same thing as electric field vectors, electric field are mathematically vectors quantity. These vectors point in the direction in which a positive test charge would move.
2. Electric field line drawings allow you to determine the approximate direction of the electric field at a point in space. Yes it is correct tangent drawn at any point on these lines gives the direction of electric filed at that point.
3. The number of electric field lines that start or end at a charged particle is proportional to the magnitude of charge on the particle, is a correct statement.
4.The electric field is strongest where the electric field lines are close together, again a correct statement as relative closeness of field lines indicate a stronger strength of electric field.
Hence we can say that all the statement are correct.
Answer:
c) 100,000 m/s
Explanation:
You need to take the same wave length from the top graph and bottom one, so let's take half a wave length then in the top one that is 0.005, but in the bottom one it's 2000/4 = 500 because they are smaller and there are 4 half waves before you get to 2000, whereas in the top one there is 1 half wave before you get to 0.005 on the graph.
Now use speed = distance / time
speed = 500 / 0.005 = 100 000 m/s
Answer:
I am not sure if this is the answer
(B) what is the height of the building if it hits the ground after those 5 seconds.
Answer:
well, in my view,
In fluid mechanics, hydrostatic equilibrium or hydrostatic balance (also known as hydrostasy) is the condition of a fluid or plastic solid at rest. This occurs when external forces such as gravity are balanced by a pressure-gradient force.
Answer:

Explanation:
Let's start finding the frequency heard by the bystander due to the moving car. We need to use Doppler effect here:
v is the speed of sound (v = 343 m/s)
So, we have:
Now, the beat frequency heard by the bystander is the combine of the frequencies, it means the difference between them. Therefore the equation is given by:
I hope it helps you!