Can you help me with this physics problem?

Hello Hello,

Can you help me with the following physics problem? Unfortunately, I can't get any further.
How big does a floating ice float 30cm thick have to be able to just about support a car weighing 1 ton?
I also have the following information: 920 kg per cubic meter and that the area of ​​the ice floe is 5 square meters. It would be very nice if you could help me 🙂

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indiachinacook
1 year ago

I interpret “just so wearable” as follows: if you put the car on the ice floes, it has to immerse it less than 30 cm deep, so just a piece of water has to remain.

Now we can easily calculate that 1 m3 of ice weighs 920 kg and, during full immersion, displaces a cubic meter of water, ie 1000 kg; Consequently, a cubic meter of ice can bear a maximum of 80 kg load. To carry the whole car, we need at least 1000/80=12.5 m3 of ice.

Our ice floe should be d=30 cm thick and should have a volume of at least V=12.5 m3, and it needs an area of ​​​​​​​​at least A=V/d=41.7 m2. This corresponds to a circle with a diameter of more than 7.3 m.

If you want to carry out the experiment in practice, I recommend the word I often use at least: to be very serious and to establish a major security factor.

Littlethought
1 year ago
Reply to  indiachinacook

Sorry, your answer wasn't visible when I wrote mine.

alterzapp
1 year ago

Water weighs 1000kg per cubic meter. Ice less like you know. This difference between the two masses ensures that the ice cholle floats. But there is also a little more difference and that is used for the car. So the difference once surface until it reaches.

Littlethought
1 year ago

It is the area size of the ice.

The acceleration of the ground is abbreviated to g.

The density of ice is according to ro(ice)=920 kg /m^3

The density of water may be assumed with crude (water) = 1000 kg / m3. This is relatively certainly not true, but the actual density of water at 0°C is somewhat lower.

We have to assume that the ice is practically completely immersed in the water.

The volume is then V =A * 0.3 m and its weight (ice) = A * 0.3 m* ro(ice) * g.

The buoyancy = V * ro(water) * g. The buoyancy must be 1000 kg *g larger than the weight of the ice.

So: lift = A * 0.3 m * ro(water) * g = 1000 kg * g + A * 0.3 m * ro(ice) * g.

Hopefully you can resolve this equation yourself to A.