Answer:
The correct option is (b).
Explanation:
We need to find the work done to increase the speed of a 1 kg toy car by 5 m/s.
We know that, the work done is equal to the kinetic energy of an object i.e.

So, 12.5 J of work is done to increase the speed of a 1.0 kg toy car by 5.0 m/s.
Answer:
Cell Death
Explanation:
Cell death is defined as the biological process which ceases the function of the cell to carry out. This can be caused due to the formation of new cells in place of old cells.
Or it can be cause due to some serious disease or may be caused due to the injury or due to the death of that organism to which these cells belong.
And another case is that when X-ray photon interact with the human cell while it passes through the cell, it will damage the cell and cease it to function well and a more drastic condition occurs and that cell become dead.
Answer:Reflection
Explanation:
The throwing back of a sound wave without absorbing it is called reflection
In acoustic reflection of sound is termed as echo i.e. sound arrived at the listener after a particular delay depending upon the position of barrier to the observer.
The reflection of sound is used in many devices like megaphone, trumpets, etc. It is also used in auditorium such that the ceiling of the auditorium is curved for multiple reflections of sound so that sound can be reached at every corner of the auditorium.