A box is put on a scale which is adjusted to read zero, when the box is empty. A stream of pebbles is then poured into the base from a height h above its bottom at a rate of n pebbles/s. Each pebble has a mass m. If the pebbles collide with the box such that they immediately come to rest after collision, then the scale reading at time t after the pebbles begin to fill the box is [ neglect piling up of pebbles]

Options

A. `mn {sqrt(2gh)) + g t}`
B. `{sqrt((2gh) + g t)}`
C. `({sqrt((2gh) + g t)})/(mn)`
D. `mn {(2gh) + g t}`

Answer

A