A small sphere of mass m is dropped from a height After it has fallen 100 m it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is-A. Greater than the work done by air friction in the second `100 m`B. Less than the work done by air friction in the second `100 m`C. Equal to `100 mg`D. Greater than `100 mg`

A small sphere of mass m is dropped from a height After it has fallen

1.	A small sphere of mass m is dropped from a height After it has fallen 100 m it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is-A. Greater than the work done by air friction in the second `100 m`B. Less than the work done by air friction in the second `100 m`C. Equal to `100 mg`D. Greater than `100 mg`
Answer» Correct Answer - B In the first `100m` body starts from rest and its velocity goes on increasing and after `100m` it acquire maximum velocity (terminal velocity). Further, air friction i.e viscous force which is proportional to velocity is low in the beginning and maximum at `v=v_(T)`.

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