a body of mass 1kg falls with an initial velocity of 14m/s from a height of 240m and penetrates into - Science - Work and Energy

Question

a body of mass 1kg falls with an initial velocity of 14m/s from a
height of 240m and penetrates into sand to a depth of 0 2m By
applying the law of conservation of energy determine the mean
resistive force of the sand

Aditi · Accepted Answer

Hi Asiya,
Please find below the solution to the asked query:
PE of the body initially = mgh = (1)(10)(240) = 2400 J
The potential energy of the stone at height 240 m = the kinetic
energy of the bullet just before hitting the ground
So, KE of the bullet when it hits the ground = 2400 J
The resistive force (say, F) offered by the sand will work to
reduce the KE of the bullet to zero
So, F s = 2400 J = [s is the distance through which stone
buries]
Since, F and s are directed oppositely, so,
-F × 0 2 = 2400
=> -F(0 2) = 2400
=> F = - 12000 N
To practice with some more questions following are the links of
the similar queries as asked by you:

https://www meritnation
com/ask-answer/question/a-car-of-mass-nine-hundred-kg-is-travelling-at-a-steady-spee/work-and-energy/8701781
https://www meritnation
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Hope this information will clear your doubts about Work and
energy
If you have any more doubts just ask here on the forum and our
experts will try to help you out as soon as possible
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a body of mass 1kg falls with an initial velocity of 14m/s from a height of 240m and penetrates into sand to a depth of 0.2m.By applying the law of conservation of energy determine the mean resistive force of the sand.