What happens to water level?

An ice cube is floating with a ball of lead inside it. When all the ice melts, what happens to the water level?

NOTE-
1) Take density of ice to be less than density of water.
2) Density of lead > Density of water.

Decreases Increases Information Insufficient Remains Same

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

4 solutions

Avineil Jain
Mar 19, 2014

When the ice is floating,

d w a t e r v d i s p l a c e d g = ( M i c e + m l e a d ) g d_{water} v_{displaced} g = (M_{ice} + m_{lead} )g

Therefore, v d i s p l a c e d = ( M i c e + m l e a d ) d w a t e r v_{displaced} = \frac{(M_{ice} + m_{lead} )}{d_{water}}

When all the ice melts, it gets converted into water so volume displaced by it will be same as before. But, since the lead ball sinks in water, using Archimedes priciple, V d i s p l a c e d = m l e a d d l e a d V_{displaced} = \frac{m_{lead}}{d_{lead}}

Now, the total volume displaced is

V d i s p l a c e d = M i c e d w a t e r + m l e a d d l e a d V_{displaced} = \frac{M_{ice}}{d_{water}} + \frac{m_{lead}}{d_{lead}}

Since, d l e a d > d w a t e r d_{lead} > d_{water}

The final volume displaced is less than initial volume displaced. \textbf{The final volume displaced is less than initial volume displaced.}

S o , w a t e r l e v e l f a l l s ! So, water level falls!

ice above the water also melts hence there would more water and hence water level increases

Prajwal Kavad - 7 years ago
John M.
Sep 5, 2014

Actually the answer is "Insufficient Information," for we're not given that the ball doesn't disappear by the time the ice cube decides to melt.

But of course everyone assumes that Newtonian mechanics will rule all the time, and that's good enough for a commonthinker anyway.

Yes even I think so but I think that the answer is insufficient information because we do not know whether the ice is in the water completely or halfway?

Aryan Mehra - 6 years, 2 months ago
Krishna Das
Mar 17, 2014

dont use Archimedes principle use the law of flotation Let the mass of the lead shot be m then mass of water displaced is also m (first law of flotation). volume of water displaced v1 =mc.c (density of water 1g/c.c). When ice melts lead ball will sink. Then volume of water displaced= volume of lead shot v2 =(m/d )c.c, where d is the density of lead since d is grater than 1 v2 is less than v1 so level will fall

it can be understood by the concept of Archimedes Principle also..

Simran Gade - 7 years, 1 month ago
Jinay Patel
Mar 7, 2014

That's too easy , the answer is that the water level will decreases.

how?

Archiet Dev - 7 years, 3 months ago

Log in to reply

Try researching about the Archimedes Principle.

If the density of an object is lower than the liquid, the object will float. Otherwise it will sink and the the water level will increase.

but I don't quite get how the water level decreased since the lead should sink and INCREASE water level.

John Shadrach Abalos - 7 years, 3 months ago

Log in to reply

same doubt from my side!

Viraj Mohile - 7 years, 3 months ago

Frm me 2.. :/ ...lead ball?

vansh puri - 7 years, 3 months ago

i agree with u ....i used the same principle....

Sayam Chakravarty - 7 years, 2 months ago

Thanks...

Archiet Dev - 7 years, 1 month ago

Note that the lead pellet which was already in the block, with the ice were partially floating. The ice block contains more air than water-ice and is in the ratio of 11:9. When the ice melts, and leaves behind the water and the pellet (whose dimensions are small compared to the ice block), increasing the water level, but the air, which is in a greater ratio, escapes, decreasing the present (displaced) water level . Thereby decreasing, the overall water level.

Hem Shailabh Sahu - 6 years, 3 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...