Question

a stone is dropped from top of height 100m/s. the stone pentrates in sand on ground through a distance of 2m calculate retardation

Answer 1

Retardation would be
Retardation =height divded by distance
=100 divide 2
=50

Answer 2

Answer:

the stone is being dropped from the top of a tower of hright 100 m. which means the potential energy is being converted to kinetic energy.

just before hitting the sand:

potential energy = kinetic enegy

mgh = (1mu²) / 2

u² = (2mgh) / m

u² = 2gh

u² = 2 × 9.8 × 100

u² = 1960

and we also know that:

v² = u² + 2as

as the retardation is negative the sign will get changed to:

v² = u² - 2as we will take the final velocity as 0 because the stone comes to rest after hitting the sand.

0 = 1960 - 2 × a × 2   ( given: the stone penetrates in the sand on the ground through a distance of 2m )

-4a = -1960

a= 490 m/s²

Hope it helps You...

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