<span>velocity is defined as the rate of change of displacement irrespective of the length of the path travelled while speed is the average rate of covering distance. but in the liming case where the instantaneous velocity is given as v=dx/dt where dx is the small displacement in a small interval dt, both the speed and velocity have the same magnitude and the direction of velocity is the direction of the tangent to the corresponding displacement-time curve.</span>
Your answer is A, Ocean Waves- because A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. Ocean waves do just that :)
Hope this helps!!
A. Made of the marble.
the mass remains constant when you drop the marble but the rest of the variables change as the marble is dropped, therefore, the only constant variable is its mass.
Answer:

Explanation:
Given:
Thickness of the paperweight cube, 
apparent depth from one side of the inbuilt paper in the plastic cube, 
apparent depth from the other side of the inbuilt paper in the plastic cube, 
Now as we know that refractive index is given as:

- Let the real depth form first side of the slab be,

- Then the depth from the second side of the slab will be,

Since refractive index for an amorphous solid is an isotropic quantity so it remains same in all the direction for this plastic.




Now the refractive index:


