30. A body of mass 10 kg is dropped from ae isheight of 20 m. Find (i)

1.	30. A body of mass 10 kg is dropped from ae isheight of 20 m. Find (i) its potential energybefore it is dropped, (ii) its kinetic energywhen it is 8 m above the ground and (iii) itskinetic energy when it hits the ground.reisandr toTake g10 ms-2
Answer» At any point of the time total sum of P.E + K.E will always be constant so, P.E at start = mgh = 101020 = 2000J and loss in P.E when it is at 8 m above the ground will be equal to gain in K.E so, K.E = mg(20-8) = 101012 = 1200J and K.E at bottom = P.E at top = 2000J and Please.. tag the Correct grade and subject to your question. This isn't a 7th grade questions and doesn't even fall under mathematics.

30. A body of mass 10 kg is dropped from ae isheight of 20 m. Find (i) its potential energybefore it is dropped, (ii) its kinetic energywhen it is 8 m above the ground and (iii) itskinetic energy when it hits the ground.reisandr toTake g10 ms-2

Answer»

At any point of the time total sum of P.E + K.E will always be constant

so, P.E at start = mgh = 10*10*20 = 2000J

and loss in P.E when it is at 8 m above the ground will be equal to gain in K.E

so, K.E = mg(20-8) = 10*10*12 = 1200J

and K.E at bottom = P.E at top = 2000J

and Please.. tag the Correct grade and subject to your question.

This isn't a 7th grade questions and doesn't even fall under mathematics.