Solving Physics Problem: Hot & Cold Liquids w/Formulas

  • Thread starter Thread starter Zygotic Embryo
  • Start date Start date
  • Tags Tags
    Physics
AI Thread Summary
The discussion focuses on solving a physics problem involving the mixing of hot and cold liquids using a specific formula for temperature calculation. The user seeks assistance in applying the formula T = (ah + bc) / (a + b) to find the initial temperatures of hot tea and cold milk based on two different mixing ratios and resulting temperatures. The first ratio of 9:1 yields a mixture temperature of 117 degrees, while a 2:1 ratio results in 96 degrees. Participants suggest setting up equations based on these ratios, simplifying them, and using algebraic methods to isolate and solve for the temperatures of the tea and milk. The conversation emphasizes the importance of showing work and applying algebraic techniques to reach the solution.
Zygotic Embryo
Messages
29
Reaction score
0
Hello, I am just starting Physics. ( Sophmore in high school)

I need some help, understanding and solving this problem.


When you mix hot and cold liquids you can find the temperature of the mixture by using the formula T= ah+bc divided by a+b, where T is the temperature of the mixture, h is the temperature of the hot liquid, c is the temperature of the cold liquid, a and b respresent the amounts of hot and cold liquids. Suppose you mix hot tea and cold milk in a ratio a:b of 9:1 and find that the temperature of the mixture is 117degrees You then change the trea:milk ratio to 2:1 and the temperature drops 96degrees. Find the initial temperatures of the tea and Milk.

Again, I can solve it Logically. But using Formula's ( showing your work ) I am not very found of..

Can someone show how to go about this. Thanks!
 
Physics news on Phys.org
Can't you solve it using simple algebra?

For your first ratio, you would just plug in your values, and it would look something like this:

117=(9h/10)+(c/10)
for the second:
96=(2h/3)+(c/3)

Simplify them and work them out separately, until you have both of the variables (h and c) on one side for both equations.

You can then have "h" equal something ±c, then in the second equation inject what h equals into h's place. Solve the equation for c, then solve the first equation as you would a one-variable algebraic equation.
 
Last edited:
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top