Temperature and pressure question

AI Thread Summary
The discussion revolves around calculating the maximum temperature in a volleyball upon impact with the ground, given its mass, volume, overpressure, and the height it bounces. Overpressure is understood as the pressure above atmospheric pressure, which affects the ball's internal conditions. Participants suggest that during the bounce, the ball's kinetic energy converts to internal energy, leading to a temperature increase. The relationship between pressure, volume, and temperature is highlighted, but specific calculations remain unclear to the participants. The conversation emphasizes the need for a clearer approach to determine the temperature change based on the provided parameters.
furtivefelon
Messages
29
Reaction score
0
hi everyone!

I have the following problem:

A volley-ball of mass m=200g and volume V=8L is inflated ith the overpresure of delta P = 0.2x10^5 Pa. A ball was thrown upwards to the height of h=20m, fell down, hit the ground, and bounced at approximately the same height. The temperature of the surrounding air is T=300k. the specific heat of the air is c=0.7kJ/(kg K)
Estimate hte maximum temperature in the ball during the hit

The problem I'm having:
I don't understand what is overpressure in this context.. From what I've read on the web and the context of the question, i believe the delta P is how much over the atmospheric pressure..

Also, I'm not really sure how to approach this question.. Can someone give me a hint of what to look up? thanks alot!
 
Physics news on Phys.org
Hi! I also think overpressure means the pressure over atmospheric pressure, in other words the net pressure that affects the ball.

But I am somewhat fuzzy on exactly what should be done here, but I think the idea is that at some point during the bounce, all of the balls kinetic energy from the fall has trasnfered into its internal energy. Internal energy again is directly proportional to temperature, so you should get the change in temperature.
 
Pressure = Overpressure + p_o = 1 atm (101325 Pa)
Pressure = p_o (1 atm (101325 Pa)) - Underpressure

If a bottle has the overpressure of 2,5 atm then it has a total pressure of 3,5 atm

If a bottle has the underpressure of 0,25 atm then it has a total pressure of 0,75 atm
 
After some more thinking, i figured that since the ball bounces and at one moment, it deforms as it hits the ground. Since the internal pressure increases because of the smaller volumne, the pressure increases accordingly, and temperature increases as well.. However, i don't know how to calculate the temperature with the given parameter..
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top