Question

An empty plastic box of mass m is found to accelerate up at the rate of g/6 when placed deep inside water. How much sand should be put inside the box so that it may accelerate down at the rate of g/6?

Answer 1

Given :

Let U be the upward force of water acting on the plastic box.

Let m be the initial mass of the plastic box.

When the empty plastic box is accelerating upward,

U-mg=mg/6

⇒U=7 mg/6

m=6U/7g                ….(i)

Let M be the final mass of the box after putting some sand in it.

Mg-U=Mg/6

⇒Mg-Mg/6=U

⇒M=6U/5g                ….ii

Mass added =6U/5g-6U/7g

=6U(7-5)g/ 35 g

=6Ux2g/35

From equation (i),

m=6U/7g

∴ Mass added =2/5m

Answer 2

Answer:

Away from the crowds of cities, in a far flung village, lived a boy named ravi . Ravi became an orphanvwhen he was still a baby . one day, an old woman came to his hut and said ______________ Complete the story