Answer:

Explanation:
The change in kinetic energy will be simply the difference between the final and initial kinetic energies: 
We know that the formula for the kinetic energy for an object is:

where <em>m </em>is the mass of the object and <em>v</em> its velocity.
For our case then we have:

Which for our values is:

Answer:So the answer is B
Explanation: When the light rays either bend or change their direction while passing from one medium to another it is called refraction of light. The refraction of light takes place when light travels from air into glass, from glass into air, from air into water or from water into air.
Explanation:
Distance travelled = Area under the line
= ut + ½ (v-u)t
Acceleration (a) = (v-u)/t and so (v-u) = at
Therefore,
Distance travelled (s) = ut + ½ (v-u)t = ut + ½ (at)t = ut + ½ at²
Thus,proved.
Answer:
of the velocity of a full size plane in the air
Answer:
The waves will increase in frequency
Explanation:
As the young girl moves her hand back and forth faster, it will be observed that number of back and forth motions increase every second. Also the distance between crest and trough of the wave (wavelength) will be reduced as she moves her hand back and forth faster.
Frequency = number of turns (moves) per second
The waves will increase in frequency since there will be more number of back and forth motions in every second.
Also,
The distance between crest and trough will be reduced, which implies that there will be decrease in waves wavelength.
This can also be verified using wave equation;
V = Fλ
At constant velocity,
F ∝ ¹/λ
Thus, decrease in wavelength will cause increase in frequency of the waves.
The right answer is : The waves will increase in frequency