Answer:
The seismic refraction is a geophysical principle governed by Snell's Law. Used in fields of engineering geology geotechnical engineering and exploration geophysics, seismic refraction traverses are performed using a seismograph or geophone in an array and an energy source
Lubricant is a type of oil. It smoothes surfaces. Meaning anything rubbing against the other object wont produce enough heat, which is what creates friction. Its an ideal tool to use for a lot of things.
I hope this helps :)
Answer:
Consider frames X and Y:
If X sees Y moving to his right then Y must see X moving to his right.
If this is not true then one can choose one frame over the other ( a favored frame and this is not allowed)
The correct option is A.
In science, model refers to a representation of idea, object or process which is used to describe a phenomenon that can not be directly observed.
In option A, it can be seen that protons that are inside the nucleus of an atom can not be seen with the naked eyes, that is why scientists used models to represent them.
Answer:
1)
2)
3)
Explanation:
Given:
width of river,
speed of stream with respect to the ground,
speed of the swimmer with respect to water,
<u>Now the resultant of the two velocities perpendicular to each other:</u>
<u>Now the angle of the resultant velocity form the vertical:</u>
- Now the distance swam by the swimmer in this direction be d.
so,
Now the distance swept downward:
2)
On swimming 37° upstream:
<u>The velocity component of stream cancelled by the swimmer:</u>
<u>Now the net effective speed of stream sweeping the swimmer:</u>
<u>The component of swimmer's velocity heading directly towards the opposite bank:</u>
<u>Now the angle of the resultant velocity of the swimmer from the normal to the stream</u>:
- Now let the distance swam in this direction be d'.
<u>Now the distance swept downstream:</u>
3)
Time taken in crossing the rive in case 1:
Time taken in crossing the rive in case 2: